* RE: [EXTERNAL] [PATCH 38/61] net: Prefer IS_ERR_OR_NULL over manual NULL check
From: Elad Nachman @ 2026-03-10 15:07 UTC (permalink / raw)
To: Philipp Hahn, amd-gfx@lists.freedesktop.org,
apparmor@lists.ubuntu.com, bpf@vger.kernel.org,
ceph-devel@vger.kernel.org, cocci@inria.fr,
dm-devel@lists.linux.dev, dri-devel@lists.freedesktop.org,
gfs2@lists.linux.dev, intel-gfx@lists.freedesktop.org,
intel-wired-lan@lists.osuosl.org, iommu@lists.linux.dev,
kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-block@vger.kernel.org, linux-bluetooth@vger.kernel.org,
linux-btrfs@vger.kernel.org, linux-cifs@vger.kernel.org,
linux-clk@vger.kernel.org, linux-erofs@lists.ozlabs.org,
linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-gpio@vger.kernel.org, linux-hyperv@vger.kernel.org,
linux-input@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-leds@vger.kernel.org, linux-media@vger.kernel.org,
linux-mips@vger.kernel.org, linux-mm@kvack.org,
linux-modules@vger.kernel.org, linux-mtd@lists.infradead.org,
linux-nfs@vger.kernel.org, linux-omap@vger.kernel.org,
linux-phy@lists.infradead.org, linux-pm@vger.kernel.org,
linux-rockchip@lists.infradead.org, linux-s390@vger.kernel.org,
linux-scsi@vger.kernel.org, linux-sctp@vger.kernel.org,
linux-security-module@vger.kernel.org, linux-sh@vger.kernel.org,
linux-sound@vger.kernel.org,
linux-stm32@st-md-mailman.stormreply.com,
linux-trace-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
ntfs3@lists.linux.dev, samba-technical@lists.samba.org,
sched-ext@lists.linux.dev, target-devel@vger.kernel.org,
tipc-discussion@lists.sourceforge.net, v9fs@lists.linux.dev
Cc: Igor Russkikh, Andrew Lunn, David S. Miller, Eric Dumazet,
Jakub Kicinski, Paolo Abeni, Pavan Chebbi, Michael Chan,
Potnuri Bharat Teja, Tony Nguyen, Przemek Kitszel, Taras Chornyi,
Maxime Coquelin, Alexandre Torgue, Iyappan Subramanian,
Keyur Chudgar, Quan Nguyen, Heiner Kallweit, Russell King
In-Reply-To: <20260310-b4-is_err_or_null-v1-38-bd63b656022d@avm.de>
>
>
> From: Philipp Hahn <phahn-oss@avm.de>
> Sent: Tuesday, March 10, 2026 1:49 PM
> To: amd-gfx@lists.freedesktop.org; apparmor@lists.ubuntu.com; bpf@vger.kernel.org; ceph-devel@vger.kernel.org; cocci@inria.fr; dm-devel@lists.linux.dev; dri-devel@lists.freedesktop.org; gfs2@lists.linux.dev; intel-gfx@lists.freedesktop.org; intel-wired-lan@lists.osuosl.org; iommu@lists.linux.dev; kvm@vger.kernel.org; linux-arm-kernel@lists.infradead.org; linux-block@vger.kernel.org; linux-bluetooth@vger.kernel.org; linux-btrfs@vger.kernel.org; linux-cifs@vger.kernel.org; linux-clk@vger.kernel.org; linux-erofs@lists.ozlabs.org; linux-ext4@vger.kernel.org; linux-fsdevel@vger.kernel.org; linux-gpio@vger.kernel.org; linux-hyperv@vger.kernel.org; linux-input@vger.kernel.org; linux-kernel@vger.kernel.org; linux-leds@vger.kernel.org; linux-media@vger.kernel.org; linux-mips@vger.kernel.org; linux-mm@kvack.org; linux-modules@vger.kernel.org; linux-mtd@lists.infradead.org; linux-nfs@vger.kernel.org; linux-omap@vger.kernel.org; linux-phy@lists.infradead.org; linux-pm@vger.kernel.org; linux-rockchip@lists.infradead.org; linux-s390@vger.kernel.org; linux-scsi@vger.kernel.org; linux-sctp@vger.kernel.org; linux-security-module@vger.kernel.org; linux-sh@vger.kernel.org; linux-sound@vger.kernel.org; linux-stm32@st-md-mailman.stormreply.com; linux-trace-kernel@vger.kernel.org; linux-usb@vger.kernel.org; linux-wireless@vger.kernel.org; netdev@vger.kernel.org; ntfs3@lists.linux.dev; samba-technical@lists.samba.org; sched-ext@lists.linux.dev; target-devel@vger.kernel.org; tipc-discussion@lists.sourceforge.net; v9fs@lists.linux.dev; Philipp Hahn <phahn-oss@avm.de>
> Cc: Igor Russkikh <irusskikh@marvell.com>; Andrew Lunn <andrew+netdev@lunn.ch>; David S. Miller <davem@davemloft.net>; Eric Dumazet <edumazet@google.com>; Jakub Kicinski <kuba@kernel.org>; Paolo Abeni <pabeni@redhat.com>; Pavan Chebbi <pavan.chebbi@broadcom.com>; Michael Chan <mchan@broadcom.com>; Potnuri Bharat Teja <bharat@chelsio.com>; Tony Nguyen <anthony.l.nguyen@intel.com>; Przemek Kitszel <przemyslaw.kitszel@intel.com>; Taras Chornyi <taras.chornyi@plvision.eu>; Maxime Coquelin <mcoquelin.stm32@gmail.com>; Alexandre Torgue <alexandre.torgue@foss.st.com>; Iyappan Subramanian <iyappan@os.amperecomputing.com>; Keyur Chudgar <keyur@os.amperecomputing.com>; Quan Nguyen <quan@os.amperecomputing.com>; Heiner Kallweit <hkallweit1@gmail.com>; Russell King <linux@armlinux.org.uk>
> Subject: [EXTERNAL] [PATCH 38/61] net: Prefer IS_ERR_OR_NULL over manual NULL check
> ZjQcmQRYFpfptBannerEnd
> Prefer using IS_ERR_OR_NULL() over using IS_ERR() and a manual NULL
> check.
>
> Change generated with coccinelle.
>
> To: Igor Russkikh <mailto:irusskikh@marvell.com>
> To: Andrew Lunn <mailto:andrew+netdev@lunn.ch>
> To: "David S. Miller" <mailto:davem@davemloft.net>
> To: Eric Dumazet <mailto:edumazet@google.com>
> To: Jakub Kicinski <mailto:kuba@kernel.org>
> To: Paolo Abeni <mailto:pabeni@redhat.com>
> To: Pavan Chebbi <mailto:pavan.chebbi@broadcom.com>
> To: Michael Chan <mailto:mchan@broadcom.com>
> To: Potnuri Bharat Teja <mailto:bharat@chelsio.com>
> To: Tony Nguyen <mailto:anthony.l.nguyen@intel.com>
> To: Przemek Kitszel <mailto:przemyslaw.kitszel@intel.com>
> To: Taras Chornyi <mailto:taras.chornyi@plvision.eu>
> To: Maxime Coquelin <mailto:mcoquelin.stm32@gmail.com>
> To: Alexandre Torgue <mailto:alexandre.torgue@foss.st.com>
> To: Iyappan Subramanian <mailto:iyappan@os.amperecomputing.com>
> To: Keyur Chudgar <mailto:keyur@os.amperecomputing.com>
> To: Quan Nguyen <mailto:quan@os.amperecomputing.com>
> To: Heiner Kallweit <mailto:hkallweit1@gmail.com>
> To: Russell King <mailto:linux@armlinux.org.uk>
> Cc: mailto:netdev@vger.kernel.org
> Cc: mailto:linux-kernel@vger.kernel.org
> Cc: mailto:intel-wired-lan@lists.osuosl.org
> Cc: mailto:linux-stm32@st-md-mailman.stormreply.com
> Cc: mailto:linux-arm-kernel@lists.infradead.org
> Cc: mailto:linux-usb@vger.kernel.org
> Signed-off-by: Philipp Hahn <mailto:phahn-oss@avm.de>
> ---
> drivers/net/ethernet/aquantia/atlantic/aq_ring.c | 2 +-
> drivers/net/ethernet/broadcom/tg3.c | 2 +-
> drivers/net/ethernet/chelsio/cxgb4/cxgb4_tc_flower.c | 3 +--
> drivers/net/ethernet/intel/ice/devlink/devlink.c | 2 +-
> drivers/net/ethernet/marvell/prestera/prestera_router.c | 2 +-
> drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 2 +-
> drivers/net/mdio/mdio-xgene.c | 2 +-
> drivers/net/usb/r8152.c | 2 +-
> 8 files changed, 8 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/net/ethernet/aquantia/atlantic/aq_ring.c b/drivers/net/ethernet/aquantia/atlantic/aq_ring.c
> index e270327e47fd804cc8ee5cfd53ed1b993c955c41..43edef35c4b1ff606b2f1519a07fad4c9a990ad4 100644
> --- a/drivers/net/ethernet/aquantia/atlantic/aq_ring.c
> +++ b/drivers/net/ethernet/aquantia/atlantic/aq_ring.c
> @@ -810,7 +810,7 @@ static int __aq_ring_xdp_clean(struct aq_ring_s *rx_ring,
> }
>
> skb = aq_xdp_run_prog(aq_nic, &xdp, rx_ring, buff);
> - if (IS_ERR(skb) || !skb)
> + if (IS_ERR_OR_NULL(skb))
> continue;
>
> if (ptp_hwtstamp_len > 0)
> diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
> index 2328fce336447eb4a796f9300ccc0ab536ff0a35..8ed79f34f03d81184dcc12e6eaff009cb8f7756e 100644
> --- a/drivers/net/ethernet/broadcom/tg3.c
> +++ b/drivers/net/ethernet/broadcom/tg3.c
> @@ -7943,7 +7943,7 @@ static int tg3_tso_bug(struct tg3 *tp, struct tg3_napi *tnapi,
>
> segs = skb_gso_segment(skb, tp->dev->features &
> ~(NETIF_F_TSO | NETIF_F_TSO6));
> - if (IS_ERR(segs) || !segs) {
> + if (IS_ERR_OR_NULL(segs)) {
> tnapi->tx_dropped++;
> goto tg3_tso_bug_end;
> }
> diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_tc_flower.c b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_tc_flower.c
> index 3307e50426819087ad985178c4a5383f16b8e7b4..1c8a6445d4b2e3535d8f1b7908dd02d8dd2f23fa 100644
> --- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_tc_flower.c
> +++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_tc_flower.c
> @@ -1032,8 +1032,7 @@ static void ch_flower_stats_handler(struct work_struct *work)
> do {
> rhashtable_walk_start(&iter);
>
> - while ((flower_entry = rhashtable_walk_next(&iter)) &&
> - !IS_ERR(flower_entry)) {
> + while (!IS_ERR_OR_NULL((flower_entry = rhashtable_walk_next(&iter)))) {
> ret = cxgb4_get_filter_counters(adap->port[0],
> flower_entry->filter_id,
> &packets, &bytes,
> diff --git a/drivers/net/ethernet/intel/ice/devlink/devlink.c b/drivers/net/ethernet/intel/ice/devlink/devlink.c
> index 6c72bd15db6d75a1d4fa04ef8fefbd26fb6e84bd..3d08b9187fd76ca3198af28111b6f1c1765ea01e 100644
> --- a/drivers/net/ethernet/intel/ice/devlink/devlink.c
> +++ b/drivers/net/ethernet/intel/ice/devlink/devlink.c
> @@ -791,7 +791,7 @@ static void ice_traverse_tx_tree(struct devlink *devlink, struct ice_sched_node
> node->parent->rate_node);
> }
>
> - if (rate_node && !IS_ERR(rate_node))
> + if (!IS_ERR_OR_NULL(rate_node))
> node->rate_node = rate_node;
>
> traverse_children:
> diff --git a/drivers/net/ethernet/marvell/prestera/prestera_router.c b/drivers/net/ethernet/marvell/prestera/prestera_router.c
> index b036b173a308b5f994ad8538eb010fa27196988c..4492938e8a3da91d32efe8d45ccbe2eb437c0e49 100644
> --- a/drivers/net/ethernet/marvell/prestera/prestera_router.c
> +++ b/drivers/net/ethernet/marvell/prestera/prestera_router.c
> @@ -1061,7 +1061,7 @@ static void __prestera_k_arb_hw_state_upd(struct prestera_switch *sw,
> n = NULL;
> }
>
> - if (!IS_ERR(n) && n) {
> + if (!IS_ERR_OR_NULL(n)) {
> neigh_event_send(n, NULL);
> neigh_release(n);
> } else {
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> index 6827c99bde8c22db42b363d2d36ad6f26075ed50..356a4e9ce04b1fcf8786d7274d31ace404be2cf6 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -1275,7 +1275,7 @@ static int stmmac_init_phy(struct net_device *dev)
> /* Some DT bindings do not set-up the PHY handle. Let's try to
> * manually parse it
> */
> - if (!phy_fwnode || IS_ERR(phy_fwnode)) {
> + if (IS_ERR_OR_NULL(phy_fwnode)) {
> int addr = priv->plat->phy_addr;
> struct phy_device *phydev;
>
> diff --git a/drivers/net/mdio/mdio-xgene.c b/drivers/net/mdio/mdio-xgene.c
> index a8f91a4b7fed0927ee14e408000cd3a2bfb9b09a..09b30b563295c6085dc1358ac361301e5cf6b2a8 100644
> --- a/drivers/net/mdio/mdio-xgene.c
> +++ b/drivers/net/mdio/mdio-xgene.c
> @@ -265,7 +265,7 @@ struct phy_device *xgene_enet_phy_register(struct mii_bus *bus, int phy_addr)
> struct phy_device *phy_dev;
>
> phy_dev = get_phy_device(bus, phy_addr, false);
> - if (!phy_dev || IS_ERR(phy_dev))
> + if (IS_ERR_OR_NULL(phy_dev))
> return NULL;
>
> if (phy_device_register(phy_dev))
> diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c
> index 0c83bbbea2e7c322ee6339893e281237663bd3ae..73f17ebd7d40007eec5004f887a46249defd28ab 100644
> --- a/drivers/net/usb/r8152.c
> +++ b/drivers/net/usb/r8152.c
> @@ -2218,7 +2218,7 @@ static void r8152_csum_workaround(struct r8152 *tp, struct sk_buff *skb,
>
> features &= ~(NETIF_F_SG | NETIF_F_IPV6_CSUM | NETIF_F_TSO6);
> segs = skb_gso_segment(skb, features);
> - if (IS_ERR(segs) || !segs)
> + if (IS_ERR_OR_NULL(segs))
> goto drop;
>
> __skb_queue_head_init(&seg_list);
>
> --
> 2.43.0
>
>
Acked-by: Elad Nachman <enachman@marvell.com>
^ permalink raw reply
* Re: [PATCH RFC 3/3] locking: Wire up contended_release tracepoint
From: Dmitry Ilvokhin @ 2026-03-10 15:12 UTC (permalink / raw)
To: Steven Rostedt
Cc: Dennis Zhou, Tejun Heo, Christoph Lameter, Masami Hiramatsu,
Mathieu Desnoyers, Peter Zijlstra, Ingo Molnar, Will Deacon,
Boqun Feng, Waiman Long, linux-mm, linux-kernel,
linux-trace-kernel, kernel-team
In-Reply-To: <20260305105924.7069eb23@gandalf.local.home>
On Thu, Mar 05, 2026 at 10:59:24AM -0500, Steven Rostedt wrote:
> On Wed, 4 Mar 2026 16:56:17 +0000
> Dmitry Ilvokhin <d@ilvokhin.com> wrote:
>
> > @@ -204,6 +206,8 @@ static inline void rwbase_write_unlock(struct rwbase_rt *rwb)
> > unsigned long flags;
> >
> > raw_spin_lock_irqsave(&rtm->wait_lock, flags);
> > + if (rt_mutex_has_waiters(rtm))
> > + trace_contended_release(rwb);
>
> Hmm, if statements should never be used just for tracepoints without a
> static branch. The above should be:
>
> if (trace_contended_release_enabled() && rt_mutex_has_waiters(rtm))
> trace_contended_release(rwb);
>
> The above "trace_contened_release_enabled()" is a static_branch where it
> turns the if statement into a nop when the tracepoint is not enabled, and a
> jmp when it is.
Thanks for catching this, Steven. Fixed locally.
^ permalink raw reply
* Re: [PATCH] tracing: Add persistent ring buffer selftest
From: Masami Hiramatsu @ 2026-03-10 15:16 UTC (permalink / raw)
To: Masami Hiramatsu (Google)
Cc: Steven Rostedt, Mathieu Desnoyers, linux-kernel,
linux-trace-kernel
In-Reply-To: <177313777313.3322014.12042708486605360066.stgit@mhiramat.tok.corp.google.com>
Hi Steve,
Here is a patch to add a selftest for the persistent ring buffer.
I think we can extend this to add more test pattern, but maybe
we can test one pattern at once.
Thank you,
On Tue, 10 Mar 2026 19:16:13 +0900
"Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote:
> From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
>
> Add a self-destractive test for the persistent ring buffer. This
> will invalidate some sub-buffer pages in the persistent ring buffer
> when kernel gets panic, and check whether the number of detected
> invalid pages is the same as record after reboot.
>
> This can ensure the kernel correctly recover partially corrupted
> persistent ring buffer when boot.
>
> The test only runs on the persistent ring buffer whose name is
> "ptracingtest". And user has to fill it up with events before
> kernel panics.
>
> To run the test, enable CONFIG_RING_BUFFER_PERSISTENT_SELFTEST
> and you have to setup the kernel cmdline;
>
> reserve_mem=20M:2M:trace trace_instance=ptracingtest^traceoff@trace
> panic=1
>
> And run following commands after the 1st boot;
>
> cd /sys/kernel/tracing/instances/ptracingtest
> echo 1 > tracing_on
> echo 1 > events/enable
> sleep 3
> echo c > /proc/sysrq-trigger
>
> After panic message, the kernel will reboot and run the verification
> on the persistent ring buffer, e.g.
>
> Ring buffer meta [1] invalid buffer page detected
> Ring buffer meta [1] is from previous boot! (318 pages discarded)
> Ring buffer testing [1]: PASSED (318/318)
>
> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> ---
> include/linux/ring_buffer.h | 1 +
> kernel/trace/Kconfig | 15 +++++++++++++
> kernel/trace/ring_buffer.c | 51 +++++++++++++++++++++++++++++++++++++++++++
> kernel/trace/trace.c | 4 +++
> 4 files changed, 71 insertions(+)
>
> diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
> index 876358cfe1b1..927b6e8587cb 100644
> --- a/include/linux/ring_buffer.h
> +++ b/include/linux/ring_buffer.h
> @@ -238,6 +238,7 @@ int ring_buffer_subbuf_size_get(struct trace_buffer *buffer);
>
> enum ring_buffer_flags {
> RB_FL_OVERWRITE = 1 << 0,
> + RB_FL_TESTING = 1 << 1,
> };
>
> #ifdef CONFIG_RING_BUFFER
> diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
> index 49de13cae428..2e6f3b7c6a31 100644
> --- a/kernel/trace/Kconfig
> +++ b/kernel/trace/Kconfig
> @@ -1202,6 +1202,21 @@ config RING_BUFFER_VALIDATE_TIME_DELTAS
> Only say Y if you understand what this does, and you
> still want it enabled. Otherwise say N
>
> +config RING_BUFFER_PERSISTENT_SELFTEST
> + bool "Enable persistent ring buffer selftest"
> + depends on RING_BUFFER
> + help
> + Run a selftest on the persistent ring buffer which names
> + "ptracingtest" (and its backup) when panic_on_reboot by
> + invalidating ring buffer pages.
> + Note that user has to enable events on the persistent ring
> + buffer manually to fill up ring buffers before rebooting.
> + Since this invalidates the data on test target ring buffer,
> + "ptracingtest" persistent ring buffer must not be used for
> + actual tracing, but only for testing.
> +
> + If unsure, say N
> +
> config MMIOTRACE_TEST
> tristate "Test module for mmiotrace"
> depends on MMIOTRACE && m
> diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
> index a86a036b4100..44268751a02c 100644
> --- a/kernel/trace/ring_buffer.c
> +++ b/kernel/trace/ring_buffer.c
> @@ -63,6 +63,7 @@ struct ring_buffer_cpu_meta {
> unsigned long commit_buffer;
> __u32 subbuf_size;
> __u32 nr_subbufs;
> + __u32 nr_invalid;
> int buffers[];
> };
>
> @@ -2086,6 +2087,11 @@ static void rb_meta_validate_events(struct ring_buffer_per_cpu *cpu_buffer)
>
> pr_info("Ring buffer meta [%d] is from previous boot! (%d pages discarded)\n",
> cpu_buffer->cpu, discarded);
> + if (meta->nr_invalid)
> + pr_info("Ring buffer testing [%d]: %s (%d/%d)\n",
> + cpu_buffer->cpu,
> + (discarded == meta->nr_invalid) ? "PASSED" : "FAILED",
> + discarded, meta->nr_invalid);
> return;
>
> invalid:
> @@ -2488,12 +2494,57 @@ static void rb_free_cpu_buffer(struct ring_buffer_per_cpu *cpu_buffer)
> kfree(cpu_buffer);
> }
>
> +#ifdef CONFIG_RING_BUFFER_PERSISTENT_SELFTEST
> +static void rb_test_inject_invalid_pages(struct trace_buffer *buffer)
> +{
> + struct ring_buffer_per_cpu *cpu_buffer;
> + struct ring_buffer_cpu_meta *meta;
> + struct buffer_data_page *dpage;
> + unsigned long ptr;
> + int subbuf_size;
> + int invalid = 0;
> + int cpu;
> + int i;
> +
> + if (!(buffer->flags & RB_FL_TESTING))
> + return;
> +
> + guard(preempt)();
> + cpu = smp_processor_id();
> +
> + cpu_buffer = buffer->buffers[cpu];
> + meta = cpu_buffer->ring_meta;
> + ptr = (unsigned long)rb_subbufs_from_meta(meta);
> + subbuf_size = meta->subbuf_size;
> +
> + /* Invalidate even pages. */
> + for (i = 0; i < meta->nr_subbufs; i += 2) {
> + int idx = meta->buffers[i];
> +
> + dpage = (void *)(ptr + idx * subbuf_size);
> + /* Skip reader page and unused pages */
> + if (dpage == cpu_buffer->reader_page->page)
> + continue;
> + if (!local_read(&dpage->commit))
> + continue;
> + local_add(subbuf_size + 1, &dpage->commit);
> + invalid++;
> + }
> +
> + pr_info("Inject invalidated %d pages on CPU%d\n", invalid, cpu);
> + meta->nr_invalid = invalid;
> +}
> +#else /* !CONFIG_RING_BUFFER_PERSISTENT_SELFTEST */
> +#define rb_test_inject_invalid_pages(buffer) do { } while (0)
> +#endif
> +
> /* Stop recording on a persistent buffer and flush cache if needed. */
> static int rb_flush_buffer_cb(struct notifier_block *nb, unsigned long event, void *data)
> {
> struct trace_buffer *buffer = container_of(nb, struct trace_buffer, flush_nb);
>
> ring_buffer_record_off(buffer);
> + rb_test_inject_invalid_pages(buffer);
> arch_ring_buffer_flush_range(buffer->range_addr_start, buffer->range_addr_end);
> return NOTIFY_DONE;
> }
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index 23de3719f495..eccc1ff22f71 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -9336,6 +9336,8 @@ static void setup_trace_scratch(struct trace_array *tr,
> memset(tscratch, 0, size);
> }
>
> +#define TRACE_TEST_PTRACING_NAME "ptracingtest"
> +
> static int
> allocate_trace_buffer(struct trace_array *tr, struct array_buffer *buf, int size)
> {
> @@ -9348,6 +9350,8 @@ allocate_trace_buffer(struct trace_array *tr, struct array_buffer *buf, int size
> buf->tr = tr;
>
> if (tr->range_addr_start && tr->range_addr_size) {
> + if (!strcmp(tr->name, TRACE_TEST_PTRACING_NAME))
> + rb_flags |= RB_FL_TESTING;
> /* Add scratch buffer to handle 128 modules */
> buf->buffer = ring_buffer_alloc_range(size, rb_flags, 0,
> tr->range_addr_start,
>
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
^ permalink raw reply
* Re: [PATCH RFC 2/3] locking/percpu-rwsem: Extract __percpu_up_read_slowpath()
From: Dmitry Ilvokhin @ 2026-03-10 15:26 UTC (permalink / raw)
To: Peter Zijlstra
Cc: Dennis Zhou, Tejun Heo, Christoph Lameter, Steven Rostedt,
Masami Hiramatsu, Mathieu Desnoyers, Ingo Molnar, Will Deacon,
Boqun Feng, Waiman Long, linux-mm, linux-kernel,
linux-trace-kernel, kernel-team
In-Reply-To: <20260304220223.GS606826@noisy.programming.kicks-ass.net>
On Wed, Mar 04, 2026 at 11:02:23PM +0100, Peter Zijlstra wrote:
> On Wed, Mar 04, 2026 at 04:56:16PM +0000, Dmitry Ilvokhin wrote:
> > Move the percpu_up_read() slowpath out of the inline function into a new
> > __percpu_up_read_slowpath() to avoid binary size increase from adding a
> > tracepoint to an inlined function.
> >
> > Signed-off-by: Dmitry Ilvokhin <d@ilvokhin.com>
> > ---
> > include/linux/percpu-rwsem.h | 15 +++------------
> > kernel/locking/percpu-rwsem.c | 18 ++++++++++++++++++
> > 2 files changed, 21 insertions(+), 12 deletions(-)
> >
> > diff --git a/include/linux/percpu-rwsem.h b/include/linux/percpu-rwsem.h
> > index c8cb010d655e..89506895365c 100644
> > --- a/include/linux/percpu-rwsem.h
> > +++ b/include/linux/percpu-rwsem.h
> > @@ -107,6 +107,8 @@ static inline bool percpu_down_read_trylock(struct percpu_rw_semaphore *sem)
> > return ret;
> > }
> >
> > +void __percpu_up_read_slowpath(struct percpu_rw_semaphore *sem);
> > +
>
> extern for consistency with all the other declarations in this header.
>
> s/_slowpath//, the corresponding down function also doesn't have
> _slowpath on.
Thanks for the feedback, Peter. Applied both suggestions locally.
^ permalink raw reply
* Re: [PATCH 01/61] Coccinelle: Prefer IS_ERR_OR_NULL over manual NULL check
From: Markus Elfring @ 2026-03-10 15:41 UTC (permalink / raw)
To: Philipp Hahn, cocci, Julia Lawall
Cc: amd-gfx, apparmor, bpf, ceph-devel, dm-devel, dri-devel, gfs2,
intel-gfx, intel-wired-lan, iommu, kvm, linux-arm-kernel,
linux-block, linux-bluetooth, linux-btrfs, linux-cifs, linux-clk,
linux-erofs, linux-ext4, linux-fsdevel, linux-gpio, linux-hyperv,
linux-input, linux-kernel, linux-leds, linux-media, linux-mips,
linux-mm, linux-modules, linux-mtd, linux-nfs, linux-omap,
linux-phy, linux-pm, linux-rockchip, linux-s390, linux-scsi,
linux-sctp, linux-security-module, linux-sh, linux-sound,
linux-stm32, linux-trace-kernel, linux-usb, linux-wireless,
netdev, nicolas.palix, ntfs3, samba-technical, sched-ext,
target-devel, tipc-discussion, v9fs
In-Reply-To: <20260310-b4-is_err_or_null-v1-1-bd63b656022d@avm.de>
> Find and convert uses of IS_ERR() plus NULL check to IS_ERR_OR_NULL().
…
Can this information trigger any more consequences on corresponding summary phrases?
…
> +++ b/scripts/coccinelle/api/is_err_or_null.cocci
> @@ -0,0 +1,125 @@
…
> +virtual patch
> +virtual report
> +virtual org
How will interests evolve further for the support of the operation mode “context”?
> +@p1 depends on patch@
> +expression E;
> +@@
> +(
> +- E != NULL && !IS_ERR(E)
> ++ !IS_ERR_OR_NULL(E)
> +|
> +- E == NULL || IS_ERR(E)
> ++ IS_ERR_OR_NULL(E)
> +|
> +- !IS_ERR(E) && E != NULL
> ++ !IS_ERR_OR_NULL(E)
> +|
> +- IS_ERR(E) || E == NULL
> ++ IS_ERR_OR_NULL(E)
> +)
Did you eventually check probabilities for the occurrence of mentioned case distinctions?
> +@p2 depends on patch@
…
I suggest to reconsider “side effects” according to the splitting of these SmPL rules
once more.
…
> +@r2 depends on report || org@
> +identifier I;
> +expression E;
> +position p;
> +@@
> +(
> +* (I = E) != NULL && ... && !IS_ERR@p(I)
> +|
> +* (I = E) == NULL || ... || IS_ERR@p(I)
> +)
I doubt that the usage of SmPL asterisks fits to these two operation modes.
…
> +@p5 depends on patch disable unlikely @
> +expression E;
> +@@
> +-\( likely \| unlikely \)(
> +(
> + IS_ERR_OR_NULL(E)
> +|
> + !IS_ERR_OR_NULL(E)
> +)
> +-)
* Would it be nicer to move such SmPL code to the end of the patch rule listing?
* Can this source code search pattern matter also for further operation modes?
Regards,
Markus
^ permalink raw reply
* Re: [PATCH RFC 1/3] locking: Add contended_release tracepoint
From: Dmitry Ilvokhin @ 2026-03-10 15:58 UTC (permalink / raw)
To: Masami Hiramatsu
Cc: Dennis Zhou, Tejun Heo, Christoph Lameter, Steven Rostedt,
Mathieu Desnoyers, Peter Zijlstra, Ingo Molnar, Will Deacon,
Boqun Feng, Waiman Long, linux-mm, linux-kernel,
linux-trace-kernel, kernel-team
In-Reply-To: <20260305075552.0840e6b107dd9560e09e4f86@kernel.org>
On Thu, Mar 05, 2026 at 07:55:52AM +0900, Masami Hiramatsu wrote:
> On Wed, 4 Mar 2026 16:56:15 +0000
> Dmitry Ilvokhin <d@ilvokhin.com> wrote:
>
> > Add the contended_release trace event. This tracepoint fires on the
> > holder side when a contended lock is released, complementing the
> > existing contention_begin/contention_end tracepoints which fire on the
> > waiter side.
> >
> > This enables correlating lock hold time under contention with waiter
> > events by lock address. Subsequent patches wire this tracepoint into
> > the individual lock implementations.
> >
>
> OK, but I don't recommend you to split the traceevent definition
> and its usage. Could you combine [1/3] and [3/3], so that we can
> understand why this event is introduced and where it is recorded
> by checking one commit?
Thanks, Masami, absolutely. I'll squash these commits.
^ permalink raw reply
* [PATCH] rtla: Fix segfault on multiple SIGINTs
From: Tomas Glozar @ 2026-03-10 16:07 UTC (permalink / raw)
To: Steven Rostedt
Cc: John Kacur, Luis Goncalves, Crystal Wood, Costa Shulyupin,
Wander Lairson Costa, LKML, linux-trace-kernel, Tomas Glozar
Detach stop_trace() from SIGINT/SIGALRM on tool clean-up to prevent it
from crashing RTLA by accessing freed memory.
This prevents a crash when multiple SIGINTs are received.
Fixes: d6899e560366 ("rtla/timerlat_hist: Abort event processing on second signal")
Fixes: 80967b354a76 ("rtla/timerlat_top: Abort event processing on second signal")
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
---
tools/tracing/rtla/src/common.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/tools/tracing/rtla/src/common.c b/tools/tracing/rtla/src/common.c
index ceff76a62a30..51cdf86d60d0 100644
--- a/tools/tracing/rtla/src/common.c
+++ b/tools/tracing/rtla/src/common.c
@@ -39,6 +39,18 @@ static void set_signals(struct common_params *params)
}
}
+/*
+ * unset_signals - unsets the signals to stop the tool
+ */
+static void unset_signals(struct common_params *params)
+{
+ signal(SIGINT, SIG_DFL);
+ if (params->duration) {
+ alarm(0);
+ signal(SIGALRM, SIG_DFL);
+ }
+}
+
/*
* common_parse_options - parse common command line options
*
@@ -284,7 +296,7 @@ int run_tool(struct tool_ops *ops, int argc, char *argv[])
retval = ops->main(tool);
if (retval)
- goto out_trace;
+ goto out_signals;
if (params->user_workload && !params->user.stopped_running) {
params->user.should_run = 0;
@@ -306,6 +318,8 @@ int run_tool(struct tool_ops *ops, int argc, char *argv[])
if (ops->analyze)
ops->analyze(tool, stopped);
+out_signals:
+ unset_signals(params);
out_trace:
trace_events_destroy(&tool->record->trace, params->events);
params->events = NULL;
--
2.53.0
^ permalink raw reply related
* Re: [PATCH] rtla: Fix segfault on multiple SIGINTs
From: Wander Lairson Costa @ 2026-03-10 16:24 UTC (permalink / raw)
To: Tomas Glozar
Cc: Steven Rostedt, John Kacur, Luis Goncalves, Crystal Wood,
Costa Shulyupin, LKML, linux-trace-kernel
In-Reply-To: <20260310160725.144443-1-tglozar@redhat.com>
On Tue, Mar 10, 2026 at 05:07:25PM +0100, Tomas Glozar wrote:
> Detach stop_trace() from SIGINT/SIGALRM on tool clean-up to prevent it
> from crashing RTLA by accessing freed memory.
>
> This prevents a crash when multiple SIGINTs are received.
>
> Fixes: d6899e560366 ("rtla/timerlat_hist: Abort event processing on second signal")
> Fixes: 80967b354a76 ("rtla/timerlat_top: Abort event processing on second signal")
> Signed-off-by: Tomas Glozar <tglozar@redhat.com>
> ---
Reviewed-by: Wander Lairson Costa <wander@redhat.com>
[...]
^ permalink raw reply
* [PATCH v2 1/2] locking/percpu-rwsem: Extract __percpu_up_read()
From: Dmitry Ilvokhin @ 2026-03-10 17:49 UTC (permalink / raw)
To: Dennis Zhou, Tejun Heo, Christoph Lameter, Steven Rostedt,
Masami Hiramatsu, Mathieu Desnoyers, Peter Zijlstra, Ingo Molnar,
Will Deacon, Boqun Feng, Waiman Long
Cc: linux-mm, linux-kernel, linux-trace-kernel, kernel-team,
Dmitry Ilvokhin
In-Reply-To: <cover.1773164180.git.d@ilvokhin.com>
Move the percpu_up_read() slowpath out of the inline function into a new
__percpu_up_read() to avoid binary size increase from adding a
tracepoint to an inlined function.
Signed-off-by: Dmitry Ilvokhin <d@ilvokhin.com>
---
include/linux/percpu-rwsem.h | 15 +++------------
kernel/locking/percpu-rwsem.c | 18 ++++++++++++++++++
2 files changed, 21 insertions(+), 12 deletions(-)
diff --git a/include/linux/percpu-rwsem.h b/include/linux/percpu-rwsem.h
index c8cb010d655e..39d5bf8e6562 100644
--- a/include/linux/percpu-rwsem.h
+++ b/include/linux/percpu-rwsem.h
@@ -107,6 +107,8 @@ static inline bool percpu_down_read_trylock(struct percpu_rw_semaphore *sem)
return ret;
}
+extern void __percpu_up_read(struct percpu_rw_semaphore *sem);
+
static inline void percpu_up_read(struct percpu_rw_semaphore *sem)
{
rwsem_release(&sem->dep_map, _RET_IP_);
@@ -118,18 +120,7 @@ static inline void percpu_up_read(struct percpu_rw_semaphore *sem)
if (likely(rcu_sync_is_idle(&sem->rss))) {
this_cpu_dec(*sem->read_count);
} else {
- /*
- * slowpath; reader will only ever wake a single blocked
- * writer.
- */
- smp_mb(); /* B matches C */
- /*
- * In other words, if they see our decrement (presumably to
- * aggregate zero, as that is the only time it matters) they
- * will also see our critical section.
- */
- this_cpu_dec(*sem->read_count);
- rcuwait_wake_up(&sem->writer);
+ __percpu_up_read(sem);
}
preempt_enable();
}
diff --git a/kernel/locking/percpu-rwsem.c b/kernel/locking/percpu-rwsem.c
index ef234469baac..f3ee7a0d6047 100644
--- a/kernel/locking/percpu-rwsem.c
+++ b/kernel/locking/percpu-rwsem.c
@@ -288,3 +288,21 @@ void percpu_up_write(struct percpu_rw_semaphore *sem)
rcu_sync_exit(&sem->rss);
}
EXPORT_SYMBOL_GPL(percpu_up_write);
+
+void __percpu_up_read(struct percpu_rw_semaphore *sem)
+{
+ lockdep_assert_preemption_disabled();
+ /*
+ * slowpath; reader will only ever wake a single blocked
+ * writer.
+ */
+ smp_mb(); /* B matches C */
+ /*
+ * In other words, if they see our decrement (presumably to
+ * aggregate zero, as that is the only time it matters) they
+ * will also see our critical section.
+ */
+ this_cpu_dec(*sem->read_count);
+ rcuwait_wake_up(&sem->writer);
+}
+EXPORT_SYMBOL_GPL(__percpu_up_read);
--
2.52.0
^ permalink raw reply related
* [PATCH v2 2/2] locking: Add contended_release tracepoint
From: Dmitry Ilvokhin @ 2026-03-10 17:49 UTC (permalink / raw)
To: Dennis Zhou, Tejun Heo, Christoph Lameter, Steven Rostedt,
Masami Hiramatsu, Mathieu Desnoyers, Peter Zijlstra, Ingo Molnar,
Will Deacon, Boqun Feng, Waiman Long
Cc: linux-mm, linux-kernel, linux-trace-kernel, kernel-team,
Dmitry Ilvokhin
In-Reply-To: <cover.1773164180.git.d@ilvokhin.com>
Add the contended_release trace event. This tracepoint fires on the
holder side when a contended lock is released, complementing the
existing contention_begin/contention_end tracepoints which fire on the
waiter side.
This enables correlating lock hold time under contention with waiter
events by lock address.
Add trace_contended_release() calls to the slowpath unlock paths of
sleepable locks: mutex, rtmutex, semaphore, rwsem, percpu-rwsem, and
RT-specific rwbase locks. Each call site fires only when there are
blocked waiters being woken, except percpu_up_write() which always wakes
via __wake_up().
Signed-off-by: Dmitry Ilvokhin <d@ilvokhin.com>
---
include/trace/events/lock.h | 17 +++++++++++++++++
kernel/locking/mutex.c | 1 +
kernel/locking/percpu-rwsem.c | 3 +++
kernel/locking/rtmutex.c | 1 +
kernel/locking/rwbase_rt.c | 8 +++++++-
kernel/locking/rwsem.c | 9 +++++++--
kernel/locking/semaphore.c | 4 +++-
7 files changed, 39 insertions(+), 4 deletions(-)
diff --git a/include/trace/events/lock.h b/include/trace/events/lock.h
index 8e89baa3775f..4f28e41977ec 100644
--- a/include/trace/events/lock.h
+++ b/include/trace/events/lock.h
@@ -138,6 +138,23 @@ TRACE_EVENT(contention_end,
TP_printk("%p (ret=%d)", __entry->lock_addr, __entry->ret)
);
+TRACE_EVENT(contended_release,
+
+ TP_PROTO(void *lock),
+
+ TP_ARGS(lock),
+
+ TP_STRUCT__entry(
+ __field(void *, lock_addr)
+ ),
+
+ TP_fast_assign(
+ __entry->lock_addr = lock;
+ ),
+
+ TP_printk("%p", __entry->lock_addr)
+);
+
#endif /* _TRACE_LOCK_H */
/* This part must be outside protection */
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index 427187ff02db..ff9d07f3e900 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -992,6 +992,7 @@ static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock, unsigne
if (waiter) {
next = waiter->task;
+ trace_contended_release(lock);
debug_mutex_wake_waiter(lock, waiter);
__clear_task_blocked_on(next, lock);
wake_q_add(&wake_q, next);
diff --git a/kernel/locking/percpu-rwsem.c b/kernel/locking/percpu-rwsem.c
index f3ee7a0d6047..1eee51766aaf 100644
--- a/kernel/locking/percpu-rwsem.c
+++ b/kernel/locking/percpu-rwsem.c
@@ -263,6 +263,8 @@ void percpu_up_write(struct percpu_rw_semaphore *sem)
{
rwsem_release(&sem->dep_map, _RET_IP_);
+ trace_contended_release(sem);
+
/*
* Signal the writer is done, no fast path yet.
*
@@ -297,6 +299,7 @@ void __percpu_up_read(struct percpu_rw_semaphore *sem)
* writer.
*/
smp_mb(); /* B matches C */
+ trace_contended_release(sem);
/*
* In other words, if they see our decrement (presumably to
* aggregate zero, as that is the only time it matters) they
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index ccaba6148b61..3db8a840b4e8 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1466,6 +1466,7 @@ static void __sched rt_mutex_slowunlock(struct rt_mutex_base *lock)
raw_spin_lock_irqsave(&lock->wait_lock, flags);
}
+ trace_contended_release(lock);
/*
* The wakeup next waiter path does not suffer from the above
* race. See the comments there.
diff --git a/kernel/locking/rwbase_rt.c b/kernel/locking/rwbase_rt.c
index 82e078c0665a..081778934b13 100644
--- a/kernel/locking/rwbase_rt.c
+++ b/kernel/locking/rwbase_rt.c
@@ -162,8 +162,10 @@ static void __sched __rwbase_read_unlock(struct rwbase_rt *rwb,
* worst case which can happen is a spurious wakeup.
*/
owner = rt_mutex_owner(rtm);
- if (owner)
+ if (owner) {
+ trace_contended_release(rwb);
rt_mutex_wake_q_add_task(&wqh, owner, state);
+ }
/* Pairs with the preempt_enable in rt_mutex_wake_up_q() */
preempt_disable();
@@ -205,6 +207,8 @@ static inline void rwbase_write_unlock(struct rwbase_rt *rwb)
unsigned long flags;
raw_spin_lock_irqsave(&rtm->wait_lock, flags);
+ if (trace_contended_release_enabled() && rt_mutex_has_waiters(rtm))
+ trace_contended_release(rwb);
__rwbase_write_unlock(rwb, WRITER_BIAS, flags);
}
@@ -214,6 +218,8 @@ static inline void rwbase_write_downgrade(struct rwbase_rt *rwb)
unsigned long flags;
raw_spin_lock_irqsave(&rtm->wait_lock, flags);
+ if (trace_contended_release_enabled() && rt_mutex_has_waiters(rtm))
+ trace_contended_release(rwb);
/* Release it and account current as reader */
__rwbase_write_unlock(rwb, WRITER_BIAS - 1, flags);
}
diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
index ba4cb74de064..cf7d8e75ad7b 100644
--- a/kernel/locking/rwsem.c
+++ b/kernel/locking/rwsem.c
@@ -1390,6 +1390,7 @@ static inline void __up_read(struct rw_semaphore *sem)
if (unlikely((tmp & (RWSEM_LOCK_MASK|RWSEM_FLAG_WAITERS)) ==
RWSEM_FLAG_WAITERS)) {
clear_nonspinnable(sem);
+ trace_contended_release(sem);
rwsem_wake(sem);
}
preempt_enable();
@@ -1413,8 +1414,10 @@ static inline void __up_write(struct rw_semaphore *sem)
preempt_disable();
rwsem_clear_owner(sem);
tmp = atomic_long_fetch_add_release(-RWSEM_WRITER_LOCKED, &sem->count);
- if (unlikely(tmp & RWSEM_FLAG_WAITERS))
+ if (unlikely(tmp & RWSEM_FLAG_WAITERS)) {
+ trace_contended_release(sem);
rwsem_wake(sem);
+ }
preempt_enable();
}
@@ -1437,8 +1440,10 @@ static inline void __downgrade_write(struct rw_semaphore *sem)
tmp = atomic_long_fetch_add_release(
-RWSEM_WRITER_LOCKED+RWSEM_READER_BIAS, &sem->count);
rwsem_set_reader_owned(sem);
- if (tmp & RWSEM_FLAG_WAITERS)
+ if (tmp & RWSEM_FLAG_WAITERS) {
+ trace_contended_release(sem);
rwsem_downgrade_wake(sem);
+ }
preempt_enable();
}
diff --git a/kernel/locking/semaphore.c b/kernel/locking/semaphore.c
index 74d41433ba13..d46415095dd6 100644
--- a/kernel/locking/semaphore.c
+++ b/kernel/locking/semaphore.c
@@ -231,8 +231,10 @@ void __sched up(struct semaphore *sem)
else
__up(sem, &wake_q);
raw_spin_unlock_irqrestore(&sem->lock, flags);
- if (!wake_q_empty(&wake_q))
+ if (!wake_q_empty(&wake_q)) {
+ trace_contended_release(sem);
wake_up_q(&wake_q);
+ }
}
EXPORT_SYMBOL(up);
--
2.52.0
^ permalink raw reply related
* [PATCH v2 0/2] locking: contended_release tracepoint instrumentation
From: Dmitry Ilvokhin @ 2026-03-10 17:49 UTC (permalink / raw)
To: Dennis Zhou, Tejun Heo, Christoph Lameter, Steven Rostedt,
Masami Hiramatsu, Mathieu Desnoyers, Peter Zijlstra, Ingo Molnar,
Will Deacon, Boqun Feng, Waiman Long
Cc: linux-mm, linux-kernel, linux-trace-kernel, kernel-team,
Dmitry Ilvokhin
The existing contention_begin/contention_end tracepoints fire on the
waiter side. The lock holder's identity and stack can be captured at
contention_begin time (e.g. perf lock contention --lock-owner), but
this reflects the holder's state when a waiter arrives, not when the
lock is actually released.
This series adds a contended_release tracepoint that fires on the
holder side when a lock with waiters is released. This provides:
- Hold time estimation: when the holder's own acquisition was
contended, its contention_end (acquisition) and contended_release
can be correlated to measure how long the lock was held under
contention.
- The holder's stack at release time, which may differ from what perf lock
contention --lock-owner captures if the holder does significant work between
the waiter's arrival and the unlock.
The tracepoint is placed exclusively in slowpath unlock paths, so
there is no performance impact on the uncontended fast path and
expected minimal impact on binary size.
Based on the feedback on the RFC, here is v2 with the suggested fixes.
Since there were no objections to the approach, I am dropping the RFC
tag.
RFC -> v2:
- Add trace_contended_release_enabled() guard before waiter checks that
exist only for the tracepoint (Steven Rostedt).
- Rename __percpu_up_read_slowpath() to __percpu_up_read() (Peter
Zijlstra).
- Add extern for __percpu_up_read() (Peter Zijlstra).
- Squashed tracepoint introduction and usage commits (Masami Hiramatsu).
RFC: https://lore.kernel.org/all/cover.1772642407.git.d@ilvokhin.com/
Dmitry Ilvokhin (2):
locking/percpu-rwsem: Extract __percpu_up_read()
locking: Add contended_release tracepoint
include/linux/percpu-rwsem.h | 15 +++------------
include/trace/events/lock.h | 17 +++++++++++++++++
kernel/locking/mutex.c | 1 +
kernel/locking/percpu-rwsem.c | 21 +++++++++++++++++++++
kernel/locking/rtmutex.c | 1 +
kernel/locking/rwbase_rt.c | 8 +++++++-
kernel/locking/rwsem.c | 9 +++++++--
kernel/locking/semaphore.c | 4 +++-
8 files changed, 60 insertions(+), 16 deletions(-)
--
2.52.0
^ permalink raw reply
* Re: [PATCH 03/61] ceph: Prefer IS_ERR_OR_NULL over manual NULL check
From: Viacheslav Dubeyko @ 2026-03-10 18:13 UTC (permalink / raw)
To: dm-devel@lists.linux.dev, phahn-oss@avm.de,
intel-wired-lan@lists.osuosl.org, linux-erofs@lists.ozlabs.org,
linux-security-module@vger.kernel.org, kvm@vger.kernel.org,
linux-sctp@vger.kernel.org, linux-pm@vger.kernel.org,
apparmor@lists.ubuntu.com, linux-ext4@vger.kernel.org,
amd-gfx@lists.freedesktop.org, linux-clk@vger.kernel.org,
linux-mips@vger.kernel.org, linux-media@vger.kernel.org,
netdev@vger.kernel.org, iommu@lists.linux.dev,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-usb@vger.kernel.org,
sched-ext@lists.linux.dev, linux-btrfs@vger.kernel.org,
linux-bluetooth@vger.kernel.org, linux-s390@vger.kernel.org,
samba-technical@lists.samba.org, intel-gfx@lists.freedesktop.org,
linux-trace-kernel@vger.kernel.org, ntfs3@lists.linux.dev,
linux-phy@lists.infradead.org, v9fs@lists.linux.dev,
ceph-devel@vger.kernel.org, tipc-discussion@lists.sourceforge.net,
linux-mtd@lists.infradead.org, linux-scsi@vger.kernel.org,
target-devel@vger.kernel.org, linux-gpio@vger.kernel.org,
cocci@inria.fr, linux-sh@vger.kernel.org,
linux-rockchip@lists.infradead.org,
linux-stm32@st-md-mailman.stormreply.com,
linux-cifs@vger.kernel.org, linux-modules@vger.kernel.org,
linux-sound@vger.kernel.org, bpf@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, linux-input@vger.kernel.org,
linux-leds@vger.kernel.org, dri-devel@lists.freedesktop.org,
linux-hyperv@vger.kernel.org, linux-mm@kvack.org,
linux-nfs@vger.kernel.org, gfs2@lists.linux.dev,
linux-wireless@vger.kernel.org, linux-omap@vger.kernel.org
Cc: idryomov@gmail.com, Alex Markuze, slava@dubeyko.com
In-Reply-To: <20260310-b4-is_err_or_null-v1-3-bd63b656022d@avm.de>
On Tue, 2026-03-10 at 12:48 +0100, Philipp Hahn wrote:
> Prefer using IS_ERR_OR_NULL() over using IS_ERR() and a manual NULL
> check.
>
> Change generated with coccinelle.
>
> To: Ilya Dryomov <idryomov@gmail.com>
> To: Alex Markuze <amarkuze@redhat.com>
> To: Viacheslav Dubeyko <slava@dubeyko.com>
> Cc: ceph-devel@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Philipp Hahn <phahn-oss@avm.de>
> ---
> fs/ceph/dir.c | 2 +-
> fs/ceph/snap.c | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
> index 86d7aa594ea99335af3e91a95c0a418fdc1b8a8a..934250748ae4fd4c148fd27bdf91175047c2877d 100644
> --- a/fs/ceph/dir.c
> +++ b/fs/ceph/dir.c
> @@ -889,7 +889,7 @@ int ceph_handle_notrace_create(struct inode *dir, struct dentry *dentry)
> {
> struct dentry *result = ceph_lookup(dir, dentry, 0);
>
> - if (result && !IS_ERR(result)) {
> + if (!IS_ERR_OR_NULL(result)) {
> /*
> * We created the item, then did a lookup, and found
> * it was already linked to another inode we already
> diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c
> index 52b4c2684f922bfed39550311e793bfe3622cd26..528ad581be160713f91416115659e2dc6f259576 100644
> --- a/fs/ceph/snap.c
> +++ b/fs/ceph/snap.c
> @@ -902,7 +902,7 @@ int ceph_update_snap_trace(struct ceph_mds_client *mdsc,
> bad:
> err = -EIO;
> fail:
> - if (realm && !IS_ERR(realm))
> + if (!IS_ERR_OR_NULL(realm))
> ceph_put_snap_realm(mdsc, realm);
> if (first_realm)
> ceph_put_snap_realm(mdsc, first_realm);
Looks good.
Reviewed-by: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>
Thanks,
Slava.
^ permalink raw reply
* Re: [PATCH 00/61] treewide: Use IS_ERR_OR_NULL over manual NULL check - refactor
From: Kuan-Wei Chiu @ 2026-03-10 18:40 UTC (permalink / raw)
To: Philipp Hahn
Cc: amd-gfx, apparmor, bpf, ceph-devel, cocci, dm-devel, dri-devel,
gfs2, intel-gfx, intel-wired-lan, iommu, kvm, linux-arm-kernel,
linux-block, linux-bluetooth, linux-btrfs, linux-cifs, linux-clk,
linux-erofs, linux-ext4, linux-fsdevel, linux-gpio, linux-hyperv,
linux-input, linux-kernel, linux-leds, linux-media, linux-mips,
linux-mm, linux-modules, linux-mtd, linux-nfs, linux-omap,
linux-phy, linux-pm, linux-rockchip, linux-s390, linux-scsi,
linux-sctp, linux-security-module, linux-sh, linux-sound,
linux-stm32, linux-trace-kernel, linux-usb, linux-wireless,
netdev, ntfs3, samba-technical, sched-ext, target-devel,
tipc-discussion, v9fs
In-Reply-To: <20260310-b4-is_err_or_null-v1-0-bd63b656022d@avm.de>
Hi Philipp,
On Tue, Mar 10, 2026 at 12:48:26PM +0100, Philipp Hahn wrote:
> While doing some static code analysis I stumbled over a common pattern,
> where IS_ERR() is combined with a NULL check. For that there is
> IS_ERR_OR_NULL().
>
> I've written a Coccinelle patch to find and patch those instances.
> The patches follow grouped by subsystem.
>
> Patches 55-58 may be dropped as they have a (minor?) semantic change:
> They use WARN_ON() or WARN_ON_ONCE(), but only in the IS_ERR() path, not
> for the NULL check. Iff it is okay to print the warning also for NULL,
> then the patches can be applied.
>
> While generating the patch set `checkpatch` complained about mixing
> [un]likely() with IS_ERR_OR_NULL(), which already uses likely()
> internally. I found and fixed several locations, where that combination
> has been used.
Thanks for the patchset. However, I think we need a explanation for why
switching to IS_ERR_OR_NULL() is an improvement over the existing code.
IMHO, the necessity of IS_ERR_OR_NULL() often highlights a confusing or
flawed API design. It usually implies that the caller is unsure whether
a failure results in an error pointer or a NULL pointer. Rather than
doing a treewide conversion of this pattern, I believe it would be much
more meaningful to review these instances case-by-case and fix the
underlying APIs or caller logic instead.
Additionally, a treewide refactoring like this has the practical
drawback of creating unnecessary merge conflicts when backporting to
stable trees.
Regards,
Kuan-Wei
^ permalink raw reply
* [PATCH v2 0/3] tracing: Read user data from futex system call trace event
From: Steven Rostedt @ 2026-03-10 20:09 UTC (permalink / raw)
To: linux-kernel, linux-trace-kernel
Cc: Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
Thomas Gleixner, Peter Zijlstra, Brian Geffon, John Stultz,
Ian Rogers, Suleiman Souhlal
We are looking at the performance of futexes and require a bit more
information when tracing them.
The two patches here extend the system call reading of user space to
create specific handling of the futex system call. It now reads the
user space relevant data (the addr, utime and addr2), as well as
parses the flags. This adds a little smarts to the trace event as
it only shows the parameters that are relevant, as well as parses
utime as either a timespec or as val2 depending on the futex_op.
Here's an example of the new output:
sys_futex(uaddr: 0x56196292e830 (0), FUTEX_WAKE|FUTEX_PRIVATE_FLAG)
sys_futex(uaddr: 0x56196292e834 (0x4a7) tid: 1191, FUTEX_UNLOCK_PI|FUTEX_PRIVATE_FLAG)
sys_futex(uaddr: 0x56196292e834 (0) tid: 0, FUTEX_LOCK_PI|FUTEX_PRIVATE_FLAG)
sys_futex(uaddr: 0x56196292e830 (0), FUTEX_WAIT|FUTEX_PRIVATE_FLAG)
sys_futex(uaddr: 0x56196292e838 (0), FUTEX_WAIT_REQUEUE_PI|FUTEX_PRIVATE_FLAG, timespec: 0x7ffc1b91a9f0 (163.048528790), uaddr2: 0x56196292e834 (4aa), val3: 0)
sys_futex(uaddr: 0x56196292e834 (0x4aa) tid: 1194, FUTEX_LOCK_PI|FUTEX_PRIVATE_FLAG)
sys_futex(uaddr: 0x56196292e838 (0), FUTEX_WAIT_REQUEUE_PI|FUTEX_PRIVATE_FLAG, timespec: 0x7ffc1b91a9f0 (163.048528790), uaddr2: 0x56196292e834 (800004aa), val3: 0)
sys_futex(uaddr: 0x7f7ed6b29990 (0x4ab), FUTEX_WAIT_BITSET|FUTEX_CLOCK_REALTIME)
sys_futex(uaddr: 0x56196292e834 (0x800004aa) tid: 1194 (WAITERS), FUTEX_LOCK_PI|FUTEX_PRIVATE_FLAG)
sys_futex(uaddr: 0x56196292e838 (0), FUTEX_WAIT_REQUEUE_PI|FUTEX_PRIVATE_FLAG, timespec: 0x7ffc1b91a9f0 (163.048528790), uaddr2: 0x56196292e834 (800004aa), val3: 0)
sys_futex(uaddr: 0x56196292e834 (0x800004aa) tid: 1194 (WAITERS), FUTEX_LOCK_PI|FUTEX_PRIVATE_FLAG)
Changes since v1: https://lore.kernel.org/all/20260303214735.002154462@kernel.org/
- Moved the printing of the futex parameters to kernel/futex/syscall.c to
keep it closer to the actual system call.
- Moved the always_inline functions: futex_cmd_has_timeout()
and futex_cmd_has_addr2() into include/linux/futex.h so that they
can be both used by the futex and tracing syscall code.
Steven Rostedt (3):
tracing: Have futex syscall trace event show specific user data
tracing: Update futex syscall trace event to show more commands
tracing: Show TID and flags for PI futex system call trace event
----
include/linux/futex.h | 38 +++++-
kernel/futex/syscalls.c | 129 ++++++++++++++++++---
kernel/trace/trace_syscalls.c | 261 +++++++++++++++++++++++++++++++++++++++++-
3 files changed, 411 insertions(+), 17 deletions(-)
^ permalink raw reply
* [PATCH v2 2/3] tracing: Update futex syscall trace event to show more commands
From: Steven Rostedt @ 2026-03-10 20:09 UTC (permalink / raw)
To: linux-kernel, linux-trace-kernel
Cc: Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
Thomas Gleixner, Peter Zijlstra, Brian Geffon, John Stultz,
Ian Rogers, Suleiman Souhlal
In-Reply-To: <20260310200954.285663884@kernel.org>
From: Steven Rostedt <rostedt@goodmis.org>
Make the futex syscall trace event a little more smart. Have it read the
futex_op instruction to determine what else it can save and print. For the
appropriate options, it will read the utime (timespec) parameter and show
its output as well as the uaddr2.
futex_requeue_p-1154 [004] ..... 144.568339: sys_futex(uaddr: 0x5652b178d834 (0x482), FUTEX_UNLOCK_PI|FUTEX_PRIVATE_FLAG, val: 0)
futex_requeue_p-1162 [002] ..... 144.568696: sys_futex(uaddr: 0x7f763b7fece0 (2), FUTEX_WAIT|FUTEX_PRIVATE_FLAG, val: 2)
futex_requeue_p-1151 [000] ..... 144.568700: sys_futex(uaddr: 0x7f763b7fece0 (0), FUTEX_WAKE|FUTEX_PRIVATE_FLAG, val: 1)
futex_requeue_p-1162 [002] ..... 144.568705: sys_futex(uaddr: 0x7f763b7fece0 (0), FUTEX_WAKE|FUTEX_PRIVATE_FLAG, val: 1)
futex_requeue_p-1151 [000] ..... 144.568715: sys_futex(uaddr: 0x7f764369e990 (0x483), FUTEX_WAIT_BITSET|FUTEX_CLOCK_REALTIME, val: 1155)
futex_requeue_p-1155 [005] ..... 144.569420: sys_futex(uaddr: 0x5652b178d838 (0), FUTEX_WAIT_REQUEUE_PI|FUTEX_PRIVATE_FLAG, val: 0, timespec: 0x7ffdacfba500 (143.890024054), uaddr2: 0x5652b178d834 (0), val3: 0)
futex_requeue_p-1155 [005] ..... 144.569454: sys_futex(uaddr: 0x5652b178d834 (0), FUTEX_LOCK_PI|FUTEX_PRIVATE_FLAG, val: 0)
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
Changes since v1: https://lore.kernel.org/all/20260303214942.587739736@kernel.org/
- Updated to have the print processing in kernel/futex/syscall.c
include/linux/futex.h | 35 ++++++++-
kernel/futex/syscalls.c | 48 ++++++-------
kernel/trace/trace_syscalls.c | 129 +++++++++++++++++++++++++++++-----
3 files changed, 164 insertions(+), 48 deletions(-)
diff --git a/include/linux/futex.h b/include/linux/futex.h
index 9fc47aa01a8b..976fa257ab5c 100644
--- a/include/linux/futex.h
+++ b/include/linux/futex.h
@@ -82,8 +82,35 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
u32 __user *uaddr2, u32 val2, u32 val3);
int futex_hash_prctl(unsigned long arg2, unsigned long arg3, unsigned long arg4);
+static __always_inline bool futex_cmd_has_timeout(u32 cmd)
+{
+ switch (cmd) {
+ case FUTEX_WAIT:
+ case FUTEX_LOCK_PI:
+ case FUTEX_LOCK_PI2:
+ case FUTEX_WAIT_BITSET:
+ case FUTEX_WAIT_REQUEUE_PI:
+ return true;
+ }
+ return false;
+}
+
+static __always_inline bool futex_cmd_has_addr2(u32 cmd)
+{
+ switch (cmd) {
+ case FUTEX_REQUEUE:
+ case FUTEX_CMP_REQUEUE:
+ case FUTEX_WAKE_OP:
+ case FUTEX_WAIT_REQUEUE_PI:
+ return true;
+ }
+ return false;
+}
+
#ifdef CONFIG_FTRACE_SYSCALLS
-void futex_print_syscall(struct seq_buf *s, int nr_args, unsigned long *args, u32 *ptr);
+void futex_print_syscall(struct seq_buf *s, int nr_args, unsigned long *args,
+ u32 *ptr1, u32 *ptr2, unsigned long *ts1,
+ unsigned long *ts2);
#endif
#ifdef CONFIG_FUTEX_PRIVATE_HASH
@@ -119,7 +146,11 @@ static inline int futex_hash_allocate_default(void)
static inline int futex_hash_free(struct mm_struct *mm) { return 0; }
static inline int futex_mm_init(struct mm_struct *mm) { return 0; }
static inline void futex_print_syscall(struct seq_buf *s, int nr_args,
- unsigned long *args, u32 *ptr) { }
+ unsigned long *args, u32 *ptr1,
+ u32 *ptr2, unsigned long *ts1,
+ unsigned long *ts2) { }
+static __always_inline bool futex_cmd_has_timeout(u32 cmd) { return false; }
+static __always_inline bool futex_cmd_has_addr2(u32 cmd) { return false; }
#endif
#endif
diff --git a/kernel/futex/syscalls.c b/kernel/futex/syscalls.c
index a1cd512aa502..a46706d6bc6c 100644
--- a/kernel/futex/syscalls.c
+++ b/kernel/futex/syscalls.c
@@ -158,31 +158,6 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
return -ENOSYS;
}
-static __always_inline bool futex_cmd_has_timeout(u32 cmd)
-{
- switch (cmd) {
- case FUTEX_WAIT:
- case FUTEX_LOCK_PI:
- case FUTEX_LOCK_PI2:
- case FUTEX_WAIT_BITSET:
- case FUTEX_WAIT_REQUEUE_PI:
- return true;
- }
- return false;
-}
-
-static __always_inline bool futex_cmd_has_addr2(u32 cmd)
-{
- switch (cmd) {
- case FUTEX_REQUEUE:
- case FUTEX_CMP_REQUEUE:
- case FUTEX_WAKE_OP:
- case FUTEX_WAIT_REQUEUE_PI:
- return true;
- }
- return false;
-}
-
static __always_inline int
futex_init_timeout(u32 cmd, u32 op, struct timespec64 *ts, ktime_t *t)
{
@@ -229,7 +204,9 @@ static const char * __futex_cmds[] =
"FUTEX_LOCK_PI2",
};
-void futex_print_syscall(struct seq_buf *s, int nr_args, unsigned long *args, u32 *ptr)
+void futex_print_syscall(struct seq_buf *s, int nr_args, unsigned long *args,
+ u32 *ptr1, u32 *ptr2, unsigned long *ts1,
+ unsigned long *ts2)
{
unsigned int op, cmd;
bool done = false;
@@ -242,8 +219,8 @@ void futex_print_syscall(struct seq_buf *s, int nr_args, unsigned long *args, u3
switch (i) {
case 0:
seq_buf_printf(s, "uaddr: 0x%lx", args[i]);
- if (ptr) {
- u32 val = *ptr;
+ if (ptr1) {
+ u32 val = *ptr1;
if (val < 10)
seq_buf_printf(s, " (%u)", val);
else
@@ -279,6 +256,15 @@ void futex_print_syscall(struct seq_buf *s, int nr_args, unsigned long *args, u3
continue;
seq_buf_printf(s, ", timespec: 0x%lx", args[i]);
+
+ if (!ts1 || !ts2)
+ continue;
+
+ if (!*ts1 && !*ts2) {
+ seq_buf_puts(s, " (0)");
+ continue;
+ }
+ seq_buf_printf(s, " (%lu.%09lu)", *ts1, *ts2);
continue;
case 4:
if (!futex_cmd_has_addr2(cmd)) {
@@ -286,6 +272,12 @@ void futex_print_syscall(struct seq_buf *s, int nr_args, unsigned long *args, u3
continue;
}
seq_buf_printf(s, ", uaddr2: 0x%lx", args[i]);
+
+ if (!ptr2)
+ continue;
+
+ seq_buf_printf(s, " (%x)", *ptr2);
+
continue;
case 5:
seq_buf_printf(s, ", val3: %lu", args[i]);
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 8cb3af569157..de1fa97547a3 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -239,21 +239,35 @@ sys_enter_openat_print(struct syscall_trace_enter *trace, struct syscall_metadat
return trace_handle_return(s);
}
+struct futex_data {
+ u32 val1;
+ u32 val2;
+ unsigned long ts1;
+ unsigned long ts2;
+};
+
static enum print_line_t
sys_enter_futex_print(struct syscall_trace_enter *trace, struct syscall_metadata *entry,
struct trace_seq *s, struct trace_event *event, int ent_size)
{
+ struct futex_data *data;
void *end = (void *)trace + ent_size;
- void *ptr;
+ unsigned long *ts1 = NULL, *ts2 = NULL;
+ u32 *ptr1 = NULL, *ptr2 = NULL;
/* Set ptr to the user space copied area */
- ptr = (void *)trace->args + sizeof(unsigned long) * entry->nb_args;
- if (ptr + 4 > end)
- ptr = NULL;
+ data = (void *)trace->args + sizeof(unsigned long) * entry->nb_args;
+ if ((void *)data + sizeof(*data) <= end) {
+ ptr1 = &data->val1;
+ ptr2 = &data->val2;
+ ts1 = &data->ts1;
+ ts2 = &data->ts2;
+ }
trace_seq_printf(s, "%s(", entry->name);
- futex_print_syscall(&s->seq, entry->nb_args, trace->args, ptr);
+ futex_print_syscall(&s->seq, entry->nb_args, trace->args, ptr1, ptr2,
+ ts1, ts2);
trace_seq_puts(s, ")\n");
@@ -472,9 +486,9 @@ sys_enter_futex_print_fmt(struct syscall_metadata *entry, char *buf, int len)
pos += snprintf(buf + pos, LEN_OR_ZERO,
"\"uaddr: 0x%%lx (0x%%lx) cmd=%%s%%s%%s");
pos += snprintf(buf + pos, LEN_OR_ZERO,
- " val: 0x%%x timeout/val2: 0x%%llx");
+ " val: 0x%%x timeout/val2: 0x%%llx (%%lu.%%lu)");
pos += snprintf(buf + pos, LEN_OR_ZERO,
- " uaddr2: 0x%%lx val3: 0x%%x\", ");
+ " uaddr2: 0x%%lx (0x%%lx) val3: 0x%%x\", ");
pos += snprintf(buf + pos, LEN_OR_ZERO,
" REC->uaddr,");
@@ -520,10 +534,12 @@ sys_enter_futex_print_fmt(struct syscall_metadata *entry, char *buf, int len)
FUTEX_CLOCK_REALTIME);
pos += snprintf(buf + pos, LEN_OR_ZERO,
- " REC->val, REC->utime,");
+ " REC->val, REC->utime, REC->__ts1, REC->__ts2,");
pos += snprintf(buf + pos, LEN_OR_ZERO,
- " REC->uaddr, REC->val3");
+ " REC->uaddr,");
+ pos += snprintf(buf + pos, LEN_OR_ZERO,
+ " REC->__value2, REC->val3");
return pos;
}
@@ -626,7 +642,39 @@ static int __init futex_fields(struct trace_event_call *call, int offset)
ret = trace_define_field(call, "u32", arg, offset, sizeof(int), 0,
FILTER_OTHER);
if (ret)
- kfree(arg);
+ goto free;
+ offset += sizeof(int);
+
+ arg = kstrdup("__value2", GFP_KERNEL);
+ if (WARN_ON_ONCE(!arg))
+ return -ENOMEM;
+ ret = trace_define_field(call, "u32", arg, offset, sizeof(int), 0,
+ FILTER_OTHER);
+ if (ret)
+ goto free;
+ offset += sizeof(int);
+
+ arg = kstrdup("__ts1", GFP_KERNEL);
+ if (WARN_ON_ONCE(!arg))
+ return -ENOMEM;
+ ret = trace_define_field(call, "unsigned long", arg, offset,
+ sizeof(unsigned long), 0, FILTER_OTHER);
+ if (ret)
+ goto free;
+ offset += sizeof(long);
+
+ arg = kstrdup("__ts2", GFP_KERNEL);
+ if (WARN_ON_ONCE(!arg))
+ return -ENOMEM;
+ ret = trace_define_field(call, "unsigned long", arg, offset,
+ sizeof(unsigned long), 0, FILTER_OTHER);
+ if (ret)
+ goto free;
+
+ return 0;
+
+free:
+ kfree(arg);
return ret;
}
@@ -799,11 +847,51 @@ static int syscall_copy_user_array(char *buf, const char __user *ptr,
return 0;
}
+struct tp_futex_data {
+ u32 cmd;
+ const u32 __user *val1;
+ const u32 __user *val2;
+ void __user *timeout;
+};
+
+static int syscall_copy_futex(char *buf, const char __user *ptr,
+ size_t size, void *data)
+{
+ struct tp_futex_data *tp_data = data;
+ struct futex_data *fdata = (void *)buf;
+ int cmd = tp_data->cmd & FUTEX_CMD_MASK;
+ int ret;
+
+ memset(fdata, 0, sizeof(*fdata));
+
+ if (tp_data->val1) {
+ ret = __copy_from_user(&fdata->val1, tp_data->val1, 4);
+ if (ret)
+ return -1;
+ }
+
+ if (tp_data->val2 && futex_cmd_has_addr2(cmd)) {
+ ret = __copy_from_user(&fdata->val2, tp_data->val2, 4);
+ if (ret)
+ return -1;
+ }
+
+ if (tp_data->timeout && futex_cmd_has_timeout(cmd)) {
+ /* Copies both ts1 and ts2 */
+ ret = __copy_from_user(&fdata->ts1, tp_data->timeout,
+ sizeof(long) * 2);
+ if (ret)
+ return -1;
+ }
+
+ return 0;
+}
+
static int
syscall_get_futex(unsigned long *args, char **buffer, int *size, int buf_size)
{
struct syscall_user_buffer *sbuf;
- const char __user *ptr;
+ struct tp_futex_data tp_data;
char *buf;
/* buf_size of zero means user doesn't want user space read */
@@ -815,14 +903,18 @@ syscall_get_futex(unsigned long *args, char **buffer, int *size, int buf_size)
if (!sbuf)
return -1;
- ptr = (char __user *)args[0];
+ tp_data.cmd = args[1];
+ tp_data.val1 = (u32 __user *)args[0];
+ tp_data.val2 = (u32 __user *)args[4];
+ tp_data.timeout = (u64 __user *)args[3];
- *buffer = trace_user_fault_read(&sbuf->buf, ptr, 4, NULL, NULL);
+ *buffer = trace_user_fault_read(&sbuf->buf, NULL, 0,
+ syscall_copy_futex, &tp_data);
if (!*buffer)
return -1;
- /* Add room for the value */
- *size += 4;
+ /* Add room for values */
+ *size += sizeof(struct futex_data);
buf = *buffer;
@@ -833,12 +925,13 @@ static void syscall_put_futex(struct syscall_metadata *sys_data,
struct syscall_trace_enter *entry,
char *buffer)
{
- u32 *ptr;
+ struct futex_data *fdata = (void *)buffer;
+ struct futex_data *data;
/* Place the futex key into the storage */
- ptr = (void *)entry->args + sizeof(unsigned long) * sys_data->nb_args;
+ data = (void *)entry->args + sizeof(unsigned long) * sys_data->nb_args;
- *ptr = *(u32 *)buffer;
+ *data = *fdata;
}
static char *sys_fault_user(unsigned int buf_size,
--
2.51.0
^ permalink raw reply related
* [PATCH v2 3/3] tracing: Show TID and flags for PI futex system call trace event
From: Steven Rostedt @ 2026-03-10 20:09 UTC (permalink / raw)
To: linux-kernel, linux-trace-kernel
Cc: Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
Thomas Gleixner, Peter Zijlstra, Brian Geffon, John Stultz,
Ian Rogers, Suleiman Souhlal
In-Reply-To: <20260310200954.285663884@kernel.org>
From: Steven Rostedt <rostedt@goodmis.org>
For the futex system call trace event for FUTEX_LOCK_PI and
FUTEX_UNLOCK_PI commands, show the TID from the value (which is usually in
hex) as well as translate the flags (DIED and WAITERS).
pi_mutex_hammer-1098 [000] ..... 121.876928: sys_futex(uaddr: 0x560f40cc8180 (0x450) tid: 1104, FUTEX_LOCK_PI|FUTEX_PRIVATE_FLAG, val: 0, timespec: 0x7f2f9d4b1e50 (0.000100000))
pi_mutex_hammer-1128 [000] ..... 121.877120: sys_futex(uaddr: 0x560f40cc8180 (0x8000042a) tid: 1066 (WAITERS), FUTEX_LOCK_PI|FUTEX_PRIVATE_FLAG, val: 0, timespec: 0x7f2f8e493e50 (0.000100000))
pi_mutex_hammer-1106 [000] ..... 121.877242: sys_futex(uaddr: 0x560f40cc8180 (0x80000452) tid: 1106 (WAITERS), FUTEX_UNLOCK_PI|FUTEX_PRIVATE_FLAG, val: 0)
This makes it easier to see the hand off of a mutex and who the owner was.
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
Changes since v1: https://lore.kernel.org/all/20260303174442.548b6524@gandalf.local.home/
- Updated to have the print processing in kernel/futex/syscall.c
kernel/futex/syscalls.c | 26 ++++++++++++++++++++++++--
1 file changed, 24 insertions(+), 2 deletions(-)
diff --git a/kernel/futex/syscalls.c b/kernel/futex/syscalls.c
index a46706d6bc6c..24d912d9b20d 100644
--- a/kernel/futex/syscalls.c
+++ b/kernel/futex/syscalls.c
@@ -211,6 +211,9 @@ void futex_print_syscall(struct seq_buf *s, int nr_args, unsigned long *args,
unsigned int op, cmd;
bool done = false;
+ op = args[1];
+ cmd = op & FUTEX_CMD_MASK;
+
for (int i = 0; !done && i < nr_args; i++) {
if (seq_buf_has_overflowed(s))
@@ -225,11 +228,30 @@ void futex_print_syscall(struct seq_buf *s, int nr_args, unsigned long *args,
seq_buf_printf(s, " (%u)", val);
else
seq_buf_printf(s, " (0x%x)", val);
+
+ switch(cmd) {
+ case FUTEX_LOCK_PI:
+ case FUTEX_UNLOCK_PI:
+ seq_buf_printf(s, " tid: %d",
+ val & FUTEX_TID_MASK);
+
+ if (!(val & (FUTEX_OWNER_DIED|FUTEX_WAITERS)))
+ break;
+
+ seq_buf_puts(s, " (");
+ if (val & FUTEX_WAITERS)
+ seq_buf_puts(s, "WAITERS");
+ if (val & FUTEX_OWNER_DIED) {
+ if (op & FUTEX_WAITERS)
+ seq_buf_putc(s, '|');
+ seq_buf_puts(s, "DIED");
+ }
+ seq_buf_putc(s, ')');
+ break;
+ }
}
continue;
case 1:
- op = args[i];
- cmd = op & FUTEX_CMD_MASK;
if (cmd <= FUTEX_LOCK_PI2)
seq_buf_printf(s, ", %s", __futex_cmds[cmd]);
else
--
2.51.0
^ permalink raw reply related
* [PATCH v2 1/3] tracing: Have futex syscall trace event show specific user data
From: Steven Rostedt @ 2026-03-10 20:09 UTC (permalink / raw)
To: linux-kernel, linux-trace-kernel
Cc: Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
Thomas Gleixner, Peter Zijlstra, Brian Geffon, John Stultz,
Ian Rogers, Suleiman Souhlal
In-Reply-To: <20260310200954.285663884@kernel.org>
From: Steven Rostedt <rostedt@goodmis.org>
Add specific reporting of the futex system call. This allows for debugging
the futex code a bit easier. Instead of just showing the values passed
into the futex system call, read the value of the user space memory
pointed to by the addr parameter.
Also make the op parameter more readable by parsing the values to show
what the command is:
futex_requeue_p-3251 [002] ..... 2101.068479: sys_futex(uaddr: 0x55e79a4da834 (0x80000cb1), FUTEX_LOCK_PI|FUTEX_PRIVATE_FLAG, val: 0)
futex_requeue_p-3248 [001] ..... 2101.068970: sys_futex(uaddr: 0x7f859072f990 (0xcb2), FUTEX_WAIT_BITSET|FUTEX_CLOCK_REALTIME, val: 3250)
futex_requeue_p-3252 [005] ..... 2101.069108: sys_futex(uaddr: 0x55e79a4da838 (0), FUTEX_WAIT_REQUEUE_PI|FUTEX_PRIVATE_FLAG, val: 0, timespec: 0x7ffe61076aa0, uaddr2: 0x55e79a4da834, uaddr2: 94453214586932, val3: 0)
futex_requeue_p-3252 [005] ..... 2101.069410: sys_futex(uaddr: 0x55e79a4da834 (0x80000cb1), FUTEX_LOCK_PI|FUTEX_PRIVATE_FLAG, val: 0)
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
Changes since v1: https://lore.kernel.org/all/20260303214942.428502100@kernel.org/
- Moved the printing of the futex parameters to kernel/futex/syscall.c to
keep it closer to the actual system call.
include/linux/futex.h | 7 +-
kernel/futex/syscalls.c | 89 ++++++++++++++++++
kernel/trace/trace_syscalls.c | 168 +++++++++++++++++++++++++++++++++-
3 files changed, 260 insertions(+), 4 deletions(-)
diff --git a/include/linux/futex.h b/include/linux/futex.h
index 9e9750f04980..9fc47aa01a8b 100644
--- a/include/linux/futex.h
+++ b/include/linux/futex.h
@@ -82,6 +82,10 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
u32 __user *uaddr2, u32 val2, u32 val3);
int futex_hash_prctl(unsigned long arg2, unsigned long arg3, unsigned long arg4);
+#ifdef CONFIG_FTRACE_SYSCALLS
+void futex_print_syscall(struct seq_buf *s, int nr_args, unsigned long *args, u32 *ptr);
+#endif
+
#ifdef CONFIG_FUTEX_PRIVATE_HASH
int futex_hash_allocate_default(void);
void futex_hash_free(struct mm_struct *mm);
@@ -114,7 +118,8 @@ static inline int futex_hash_allocate_default(void)
}
static inline int futex_hash_free(struct mm_struct *mm) { return 0; }
static inline int futex_mm_init(struct mm_struct *mm) { return 0; }
-
+static inline void futex_print_syscall(struct seq_buf *s, int nr_args,
+ unsigned long *args, u32 *ptr) { }
#endif
#endif
diff --git a/kernel/futex/syscalls.c b/kernel/futex/syscalls.c
index 743c7a728237..a1cd512aa502 100644
--- a/kernel/futex/syscalls.c
+++ b/kernel/futex/syscalls.c
@@ -171,6 +171,18 @@ static __always_inline bool futex_cmd_has_timeout(u32 cmd)
return false;
}
+static __always_inline bool futex_cmd_has_addr2(u32 cmd)
+{
+ switch (cmd) {
+ case FUTEX_REQUEUE:
+ case FUTEX_CMP_REQUEUE:
+ case FUTEX_WAKE_OP:
+ case FUTEX_WAIT_REQUEUE_PI:
+ return true;
+ }
+ return false;
+}
+
static __always_inline int
futex_init_timeout(u32 cmd, u32 op, struct timespec64 *ts, ktime_t *t)
{
@@ -207,6 +219,83 @@ SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val,
return do_futex(uaddr, op, val, tp, uaddr2, (unsigned long)utime, val3);
}
+#ifdef CONFIG_FTRACE_SYSCALLS
+static const char * __futex_cmds[] =
+{
+ "FUTEX_WAIT", "FUTEX_WAKE", "FUTEX_FD", "FUTEX_REQUEUE",
+ "FUTEX_CMP_REQUEUE", "FUTEX_WAKE_OP", "FUTEX_LOCK_PI",
+ "FUTEX_UNLOCK_PI", "FUTEX_TRYLOCK_PI", "FUTEX_WAIT_BITSET",
+ "FUTEX_WAKE_BITSET", "FUTEX_WAIT_REQUEUE_PI", "FUTEX_CMP_REQUEUE_PI",
+ "FUTEX_LOCK_PI2",
+};
+
+void futex_print_syscall(struct seq_buf *s, int nr_args, unsigned long *args, u32 *ptr)
+{
+ unsigned int op, cmd;
+ bool done = false;
+
+ for (int i = 0; !done && i < nr_args; i++) {
+
+ if (seq_buf_has_overflowed(s))
+ break;
+
+ switch (i) {
+ case 0:
+ seq_buf_printf(s, "uaddr: 0x%lx", args[i]);
+ if (ptr) {
+ u32 val = *ptr;
+ if (val < 10)
+ seq_buf_printf(s, " (%u)", val);
+ else
+ seq_buf_printf(s, " (0x%x)", val);
+ }
+ continue;
+ case 1:
+ op = args[i];
+ cmd = op & FUTEX_CMD_MASK;
+ if (cmd <= FUTEX_LOCK_PI2)
+ seq_buf_printf(s, ", %s", __futex_cmds[cmd]);
+ else
+ seq_buf_puts(s, ", UNKNOWN");
+
+ if (op & FUTEX_PRIVATE_FLAG)
+ seq_buf_puts(s, "|FUTEX_PRIVATE_FLAG");
+ if (op & FUTEX_CLOCK_REALTIME)
+ seq_buf_puts(s, "|FUTEX_CLOCK_REALTIME");
+ continue;
+ case 3:
+ if (!futex_cmd_has_timeout(cmd)) {
+
+ if (!futex_cmd_has_addr2(cmd)) {
+ done = true;
+ continue;
+ }
+
+ seq_buf_printf(s, ", val2: 0x%x", (u32)(long)args[i]);
+ continue;
+ }
+
+ if (!args[i])
+ continue;
+
+ seq_buf_printf(s, ", timespec: 0x%lx", args[i]);
+ continue;
+ case 4:
+ if (!futex_cmd_has_addr2(cmd)) {
+ done = true;
+ continue;
+ }
+ seq_buf_printf(s, ", uaddr2: 0x%lx", args[i]);
+ continue;
+ case 5:
+ seq_buf_printf(s, ", val3: %lu", args[i]);
+ done = true;
+ continue;
+ }
+ }
+}
+#endif
+
/**
* futex_parse_waitv - Parse a waitv array from userspace
* @futexv: Kernel side list of waiters to be filled
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 37317b81fcda..8cb3af569157 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -6,11 +6,13 @@
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/module.h> /* for MODULE_NAME_LEN via KSYM_SYMBOL_LEN */
+#include <linux/futex.h>
#include <linux/ftrace.h>
#include <linux/perf_event.h>
#include <linux/xarray.h>
#include <asm/syscall.h>
+
#include "trace_output.h"
#include "trace.h"
@@ -237,6 +239,27 @@ sys_enter_openat_print(struct syscall_trace_enter *trace, struct syscall_metadat
return trace_handle_return(s);
}
+static enum print_line_t
+sys_enter_futex_print(struct syscall_trace_enter *trace, struct syscall_metadata *entry,
+ struct trace_seq *s, struct trace_event *event, int ent_size)
+{
+ void *end = (void *)trace + ent_size;
+ void *ptr;
+
+ /* Set ptr to the user space copied area */
+ ptr = (void *)trace->args + sizeof(unsigned long) * entry->nb_args;
+ if (ptr + 4 > end)
+ ptr = NULL;
+
+ trace_seq_printf(s, "%s(", entry->name);
+
+ futex_print_syscall(&s->seq, entry->nb_args, trace->args, ptr);
+
+ trace_seq_puts(s, ")\n");
+
+ return trace_handle_return(s);
+}
+
static enum print_line_t
print_syscall_enter(struct trace_iterator *iter, int flags,
struct trace_event *event)
@@ -267,6 +290,10 @@ print_syscall_enter(struct trace_iterator *iter, int flags,
if (!tr || !(tr->trace_flags & TRACE_ITER(VERBOSE)))
return sys_enter_openat_print(trace, entry, s, event);
break;
+ case __NR_futex:
+ if (!tr || !(tr->trace_flags & TRACE_ITER(VERBOSE)))
+ return sys_enter_futex_print(trace, entry, s, event, iter->ent_size);
+ break;
default:
break;
}
@@ -437,6 +464,69 @@ sys_enter_openat_print_fmt(struct syscall_metadata *entry, char *buf, int len)
return pos;
}
+static int __init
+sys_enter_futex_print_fmt(struct syscall_metadata *entry, char *buf, int len)
+{
+ int pos = 0;
+
+ pos += snprintf(buf + pos, LEN_OR_ZERO,
+ "\"uaddr: 0x%%lx (0x%%lx) cmd=%%s%%s%%s");
+ pos += snprintf(buf + pos, LEN_OR_ZERO,
+ " val: 0x%%x timeout/val2: 0x%%llx");
+ pos += snprintf(buf + pos, LEN_OR_ZERO,
+ " uaddr2: 0x%%lx val3: 0x%%x\", ");
+
+ pos += snprintf(buf + pos, LEN_OR_ZERO,
+ " REC->uaddr,");
+ pos += snprintf(buf + pos, LEN_OR_ZERO,
+ " REC->__value,");
+ pos += snprintf(buf + pos, LEN_OR_ZERO,
+ " __print_symbolic(REC->op & 0x%x, ", FUTEX_CMD_MASK);
+
+ pos += snprintf(buf + pos, LEN_OR_ZERO,
+ "{%d, \"FUTEX_WAIT\"}, ", FUTEX_WAIT);
+ pos += snprintf(buf + pos, LEN_OR_ZERO,
+ "{%d, \"FUTEX_WAKE\"}, ", FUTEX_WAKE);
+ pos += snprintf(buf + pos, LEN_OR_ZERO,
+ "{%d, \"FUTEX_FD\"}, ", FUTEX_FD);
+ pos += snprintf(buf + pos, LEN_OR_ZERO,
+ "{%d, \"FUTEX_REQUEUE\"}, ", FUTEX_REQUEUE);
+ pos += snprintf(buf + pos, LEN_OR_ZERO,
+ "{%d, \"FUTEX_CMP_REQUEUE\"}, ", FUTEX_CMP_REQUEUE);
+ pos += snprintf(buf + pos, LEN_OR_ZERO,
+ "{%d, \"FUTEX_WAKE_OP\"}, ", FUTEX_WAKE_OP);
+ pos += snprintf(buf + pos, LEN_OR_ZERO,
+ "{%d, \"FUTEX_LOCK_PI\"}, ", FUTEX_LOCK_PI);
+ pos += snprintf(buf + pos, LEN_OR_ZERO,
+ "{%d, \"FUTEX_UNLOCK_PI\"}, ", FUTEX_UNLOCK_PI);
+ pos += snprintf(buf + pos, LEN_OR_ZERO,
+ "{%d, \"FUTEX_TRYLOCK_PI\"}, ", FUTEX_TRYLOCK_PI);
+ pos += snprintf(buf + pos, LEN_OR_ZERO,
+ "{%d, \"FUTEX_WAIT_BITSET\"}, ", FUTEX_WAIT_BITSET);
+ pos += snprintf(buf + pos, LEN_OR_ZERO,
+ "{%d, \"FUTEX_WAKE_BITSET\"}, ", FUTEX_WAKE_BITSET);
+ pos += snprintf(buf + pos, LEN_OR_ZERO,
+ "{%d, \"FUTEX_WAIT_REQUEUE_PI\"}, ", FUTEX_WAIT_REQUEUE_PI);
+ pos += snprintf(buf + pos, LEN_OR_ZERO,
+ "{%d, \"FUTEX_CMP_REQUEUE_PI\"}, ", FUTEX_CMP_REQUEUE_PI);
+ pos += snprintf(buf + pos, LEN_OR_ZERO,
+ "{%d, \"FUTEX_LOCK_PI2\"}),", FUTEX_LOCK_PI2);
+
+ pos += snprintf(buf + pos, LEN_OR_ZERO,
+ " (REC->op & %d) ? \"|FUTEX_PRIVATE_FLAG\" : \"\",",
+ FUTEX_PRIVATE_FLAG);
+ pos += snprintf(buf + pos, LEN_OR_ZERO,
+ " (REC->op & %d) ? \"|FUTEX_CLOCK_REALTIME\" : \"\",",
+ FUTEX_CLOCK_REALTIME);
+
+ pos += snprintf(buf + pos, LEN_OR_ZERO,
+ " REC->val, REC->utime,");
+
+ pos += snprintf(buf + pos, LEN_OR_ZERO,
+ " REC->uaddr, REC->val3");
+ return pos;
+}
+
static int __init
__set_enter_print_fmt(struct syscall_metadata *entry, char *buf, int len)
{
@@ -447,6 +537,8 @@ __set_enter_print_fmt(struct syscall_metadata *entry, char *buf, int len)
switch (entry->syscall_nr) {
case __NR_openat:
return sys_enter_openat_print_fmt(entry, buf, len);
+ case __NR_futex:
+ return sys_enter_futex_print_fmt(entry, buf, len);
default:
break;
}
@@ -523,6 +615,21 @@ static void __init free_syscall_print_fmt(struct trace_event_call *call)
kfree(call->print_fmt);
}
+static int __init futex_fields(struct trace_event_call *call, int offset)
+{
+ char *arg;
+ int ret;
+
+ arg = kstrdup("__value", GFP_KERNEL);
+ if (WARN_ON_ONCE(!arg))
+ return -ENOMEM;
+ ret = trace_define_field(call, "u32", arg, offset, sizeof(int), 0,
+ FILTER_OTHER);
+ if (ret)
+ kfree(arg);
+ return ret;
+}
+
static int __init syscall_enter_define_fields(struct trace_event_call *call)
{
struct syscall_trace_enter trace;
@@ -544,6 +651,9 @@ static int __init syscall_enter_define_fields(struct trace_event_call *call)
offset += sizeof(unsigned long);
}
+ if (!ret && meta->syscall_nr == __NR_futex)
+ return futex_fields(call, offset);
+
if (ret || !meta->user_mask)
return ret;
@@ -689,6 +799,48 @@ static int syscall_copy_user_array(char *buf, const char __user *ptr,
return 0;
}
+static int
+syscall_get_futex(unsigned long *args, char **buffer, int *size, int buf_size)
+{
+ struct syscall_user_buffer *sbuf;
+ const char __user *ptr;
+ char *buf;
+
+ /* buf_size of zero means user doesn't want user space read */
+ if (!buf_size)
+ return -1;
+
+ /* If the syscall_buffer is NULL, tracing is being shutdown */
+ sbuf = READ_ONCE(syscall_buffer);
+ if (!sbuf)
+ return -1;
+
+ ptr = (char __user *)args[0];
+
+ *buffer = trace_user_fault_read(&sbuf->buf, ptr, 4, NULL, NULL);
+ if (!*buffer)
+ return -1;
+
+ /* Add room for the value */
+ *size += 4;
+
+ buf = *buffer;
+
+ return 0;
+}
+
+static void syscall_put_futex(struct syscall_metadata *sys_data,
+ struct syscall_trace_enter *entry,
+ char *buffer)
+{
+ u32 *ptr;
+
+ /* Place the futex key into the storage */
+ ptr = (void *)entry->args + sizeof(unsigned long) * sys_data->nb_args;
+
+ *ptr = *(u32 *)buffer;
+}
+
static char *sys_fault_user(unsigned int buf_size,
struct syscall_metadata *sys_data,
struct syscall_user_buffer *sbuf,
@@ -905,6 +1057,9 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
if (syscall_get_data(sys_data, args, &user_ptr,
&size, user_sizes, &uargs, tr->syscall_buf_sz) < 0)
return;
+ } else if (syscall_nr == __NR_futex) {
+ if (syscall_get_futex(args, &user_ptr, &size, tr->syscall_buf_sz) < 0)
+ return;
}
size += sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;
@@ -921,6 +1076,9 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
if (mayfault)
syscall_put_data(sys_data, entry, user_ptr, size, user_sizes, uargs);
+ else if (syscall_nr == __NR_futex)
+ syscall_put_futex(sys_data, entry, user_ptr);
+
trace_event_buffer_commit(&fbuffer);
}
@@ -971,14 +1129,18 @@ static int reg_event_syscall_enter(struct trace_event_file *file,
{
struct syscall_metadata *sys_data = call->data;
struct trace_array *tr = file->tr;
+ bool enable_faults;
int ret = 0;
int num;
num = sys_data->syscall_nr;
if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
return -ENOSYS;
+
+ enable_faults = sys_data->user_mask || num == __NR_futex;
+
guard(mutex)(&syscall_trace_lock);
- if (sys_data->user_mask) {
+ if (enable_faults) {
ret = syscall_fault_buffer_enable();
if (ret < 0)
return ret;
@@ -986,7 +1148,7 @@ static int reg_event_syscall_enter(struct trace_event_file *file,
if (!tr->sys_refcount_enter) {
ret = register_trace_sys_enter(ftrace_syscall_enter, tr);
if (ret < 0) {
- if (sys_data->user_mask)
+ if (enable_faults)
syscall_fault_buffer_disable();
return ret;
}
@@ -1011,7 +1173,7 @@ static void unreg_event_syscall_enter(struct trace_event_file *file,
WRITE_ONCE(tr->enter_syscall_files[num], NULL);
if (!tr->sys_refcount_enter)
unregister_trace_sys_enter(ftrace_syscall_enter, tr);
- if (sys_data->user_mask)
+ if (sys_data->user_mask || num == __NR_futex)
syscall_fault_buffer_disable();
}
--
2.51.0
^ permalink raw reply related
* Re: [PATCH v2 1/2] kthread: remove kthread_exit()
From: Frederic Weisbecker @ 2026-03-10 22:26 UTC (permalink / raw)
To: Christian Brauner
Cc: Linus Torvalds, linux-kernel, linux-modules, linux-nfs, bpf,
kunit-dev, linux-doc, linux-trace-kernel, netfs, io-uring, audit,
rcu, kvm, virtualization, netdev, linux-mm, linux-security-module,
Christian Loehle, linux-fsdevel
In-Reply-To: <20260310-work-kernel-exit-v2-1-30711759d87b@kernel.org>
Le Tue, Mar 10, 2026 at 03:56:09PM +0100, Christian Brauner a écrit :
> In 28aaa9c39945 ("kthread: consolidate kthread exit paths to prevent use-after-free")
> we folded kthread_exit() into do_exit() when we fixed a nasty UAF bug.
> We left kthread_exit() around as an alias to do_exit(). Remove it
> completely.
Thanks for fixing that UAF! I unfortunately missed it.
>
> Reported-by: Christian Loehle <christian.loehle@arm.com>
> Link: https://lore.kernel.org/1ff1bce2-8bb4-463c-a631-16e14f4ea7e2@arm.com
> Signed-off-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
--
Frederic Weisbecker
SUSE Labs
^ permalink raw reply
* Re: [PATCH v2 2/2] tree-wide: rename do_exit() to task_exit()
From: Frederic Weisbecker @ 2026-03-10 22:30 UTC (permalink / raw)
To: Christian Brauner
Cc: Linus Torvalds, linux-kernel, linux-modules, linux-nfs, bpf,
kunit-dev, linux-doc, linux-trace-kernel, netfs, io-uring, audit,
rcu, kvm, virtualization, netdev, linux-mm, linux-security-module,
Christian Loehle, linux-fsdevel
In-Reply-To: <20260310-work-kernel-exit-v2-2-30711759d87b@kernel.org>
Le Tue, Mar 10, 2026 at 03:56:10PM +0100, Christian Brauner a écrit :
> Rename do_exit() to task_exit() so it's clear that this is an api and
> not a hidden internal helper.
>
> Signed-off-by: Christian Brauner <brauner@kernel.org>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
--
Frederic Weisbecker
SUSE Labs
^ permalink raw reply
* Re: [PATCH v2 2/2] tree-wide: rename do_exit() to task_exit()
From: Steven Rostedt @ 2026-03-11 0:02 UTC (permalink / raw)
To: Christian Brauner
Cc: Linus Torvalds, linux-kernel, linux-modules, linux-nfs, bpf,
kunit-dev, linux-doc, linux-trace-kernel, netfs, io-uring, audit,
rcu, kvm, virtualization, netdev, linux-mm, linux-security-module,
Christian Loehle, linux-fsdevel
In-Reply-To: <20260310-work-kernel-exit-v2-2-30711759d87b@kernel.org>
On Tue, 10 Mar 2026 15:56:10 +0100
Christian Brauner <brauner@kernel.org> wrote:
> diff --git a/tools/testing/selftests/bpf/progs/tracing_failure.c b/tools/testing/selftests/bpf/progs/tracing_failure.c
> index 65e485c4468c..5144f4cc5787 100644
> --- a/tools/testing/selftests/bpf/progs/tracing_failure.c
> +++ b/tools/testing/selftests/bpf/progs/tracing_failure.c
> @@ -25,7 +25,7 @@ int BPF_PROG(tracing_deny)
> return 0;
> }
>
> -SEC("?fexit/do_exit")
> +SEC("?fexit/task_exit")
> int BPF_PROG(fexit_noreturns)
> {
> return 0;
> diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc b/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc
> index fee479295e2f..7e00d8ecd110 100644
> --- a/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc
> +++ b/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc
> @@ -82,7 +82,7 @@ check_error 'f vfs_read arg1=^' # NO_ARG_BODY
> # multiprobe errors
> if grep -q "Create/append/" README && grep -q "imm-value" README; then
> echo "f:fprobes/testevent $FUNCTION_FORK" > dynamic_events
> -check_error '^f:fprobes/testevent do_exit%return' # DIFF_PROBE_TYPE
> +check_error '^f:fprobes/testevent task_exit%return' # DIFF_PROBE_TYPE
>
> # Explicitly use printf "%s" to not interpret \1
> printf "%s" "f:fprobes/testevent $FUNCTION_FORK abcd=\\1" > dynamic_events
> diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_multiprobe.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_multiprobe.tc
> index f0d5b7777ed7..a95e3824690a 100644
> --- a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_multiprobe.tc
> +++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_multiprobe.tc
> @@ -5,7 +5,7 @@
>
> # Choose 2 symbols for target
> SYM1=$FUNCTION_FORK
> -SYM2=do_exit
> +SYM2=task_exit
> EVENT_NAME=kprobes/testevent
>
> DEF1="p:$EVENT_NAME $SYM1"
> diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_syntax_errors.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_syntax_errors.tc
> index 8f1c58f0c239..b55ea3c05cfa 100644
> --- a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_syntax_errors.tc
> +++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_syntax_errors.tc
> @@ -87,7 +87,7 @@ esac
> # multiprobe errors
> if grep -q "Create/append/" README && grep -q "imm-value" README; then
> echo "p:kprobes/testevent $FUNCTION_FORK" > kprobe_events
> -check_error '^r:kprobes/testevent do_exit' # DIFF_PROBE_TYPE
> +check_error '^r:kprobes/testevent task_exit' # DIFF_PROBE_TYPE
>
> # Explicitly use printf "%s" to not interpret \1
> printf "%s" "p:kprobes/testevent $FUNCTION_FORK abcd=\\1" > kprobe_events
These tests need to pass on old kernels too. So we can't just do a
"s/do_exit/task_exit/" conversion. It needs to test for task_exit first,
and if not found, fallback to do_exit.
See how we handled the _do_fork() > kernel_clone() rename:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/testing/selftests/ftrace/test.d/functions#n182
-- Steve
^ permalink raw reply
* Re: [PATCH 00/61] treewide: Use IS_ERR_OR_NULL over manual NULL check - refactor
From: Russell King (Oracle) @ 2026-03-11 0:09 UTC (permalink / raw)
To: Philipp Hahn
Cc: amd-gfx, apparmor, bpf, ceph-devel, cocci, dm-devel, dri-devel,
gfs2, intel-gfx, intel-wired-lan, iommu, kvm, linux-arm-kernel,
linux-block, linux-bluetooth, linux-btrfs, linux-cifs, linux-clk,
linux-erofs, linux-ext4, linux-fsdevel, linux-gpio, linux-hyperv,
linux-input, linux-kernel, linux-leds, linux-media, linux-mips,
linux-mm, linux-modules, linux-mtd, linux-nfs, linux-omap,
linux-phy, linux-pm, linux-rockchip, linux-s390, linux-scsi,
linux-sctp, linux-security-module, linux-sh, linux-sound,
linux-stm32, linux-trace-kernel, linux-usb, linux-wireless,
netdev, ntfs3, samba-technical, sched-ext, target-devel,
tipc-discussion, v9fs, Julia Lawall, Nicolas Palix, Chris Mason,
David Sterba, Ilya Dryomov, Alex Markuze, Viacheslav Dubeyko,
Theodore Ts'o, Andreas Dilger, Steve French, Paulo Alcantara,
Ronnie Sahlberg, Shyam Prasad N, Tom Talpey, Bharath SM,
Eric Van Hensbergen, Latchesar Ionkov, Dominique Martinet,
Christian Schoenebeck, Gao Xiang, Chao Yu, Yue Hu, Jeffle Xu,
Sandeep Dhavale, Hongbo Li, Chunhai Guo, Miklos Szeredi,
Konstantin Komarov, Andreas Gruenbacher, Kees Cook, Tony Luck,
Guilherme G. Piccoli, Jan Kara, Phillip Lougher, Alexander Viro,
Christian Brauner, Jan Kara, Steven Rostedt, Masami Hiramatsu,
Mathieu Desnoyers, Tejun Heo, David Vernet, Andrea Righi,
Changwoo Min, Ingo Molnar, Peter Zijlstra, Juri Lelli,
Vincent Guittot, Dietmar Eggemann, Ben Segall, Mel Gorman,
Valentin Schneider, Luis Chamberlain, Petr Pavlu, Daniel Gomez,
Sami Tolvanen, Aaron Tomlin, Sylwester Nawrocki, Liam Girdwood,
Mark Brown, Jaroslav Kysela, Takashi Iwai, Max Filippov,
Paolo Bonzini, John Johansen, Paul Moore, James Morris,
Serge E. Hallyn, Andrew Morton, Alasdair Kergon, Mike Snitzer,
Mikulas Patocka, Benjamin Marzinski, David S. Miller, David Ahern,
Eric Dumazet, Jakub Kicinski, Paolo Abeni, Simon Horman,
Marcel Holtmann, Johan Hedberg, Luiz Augusto von Dentz,
Alexei Starovoitov, Daniel Borkmann, Jesper Dangaard Brouer,
John Fastabend, Stanislav Fomichev, Jamal Hadi Salim, Jiri Pirko,
Marcelo Ricardo Leitner, Xin Long, Trond Myklebust,
Anna Schumaker, Chuck Lever, Jeff Layton, NeilBrown,
Olga Kornievskaia, Dai Ngo, Jon Maloy, Johannes Berg,
Catalin Marinas, John Crispin, Thomas Bogendoerfer,
Yoshinori Sato, Rich Felker, John Paul Adrian Glaubitz,
Andrzej Hajda, Neil Armstrong, Robert Foss, Laurent Pinchart,
Jonas Karlman, Jernej Skrabec, Maarten Lankhorst, Maxime Ripard,
Thomas Zimmermann, David Airlie, Simona Vetter, Zhenyu Wang,
Zhi Wang, Jani Nikula, Joonas Lahtinen, Rodrigo Vivi,
Tvrtko Ursulin, Alex Deucher, Christian König, Sandy Huang,
Heiko Stübner, Andy Yan, Igor Russkikh, Andrew Lunn,
Pavan Chebbi, Michael Chan, Potnuri Bharat Teja, Tony Nguyen,
Przemek Kitszel, Taras Chornyi, Maxime Coquelin, Alexandre Torgue,
Iyappan Subramanian, Keyur Chudgar, Quan Nguyen, Heiner Kallweit,
Marc Zyngier, Thomas Gleixner, Andrew Lunn, Gregory Clement,
Sebastian Hesselbarth, Vinod Koul, Linus Walleij, Ulf Hansson,
Heiko Carstens, Vasily Gorbik, Alexander Gordeev,
Christian Borntraeger, Sven Schnelle, Martin K. Petersen,
Eduardo Valentin, Keerthy, Rafael J. Wysocki, Daniel Lezcano,
Zhang Rui, Lukasz Luba, Alex Williamson, Mark Greer,
Miquel Raynal, Richard Weinberger, Vignesh Raghavendra,
Shuah Khan, Kieran Bingham, Mauro Carvalho Chehab, Joerg Roedel,
Will Deacon, Robin Murphy, Lee Jones, Pavel Machek, Dave Penkler,
K. Y. Srinivasan, Haiyang Zhang, Wei Liu, Dexuan Cui, Long Li,
Justin Sanders, Jens Axboe, Georgi Djakov, Michael Turquette,
Stephen Boyd, Philipp Zabel, Borislav Petkov, Dave Hansen, x86,
H. Peter Anvin, Pali Rohár, Dmitry Torokhov
In-Reply-To: <20260310-b4-is_err_or_null-v1-0-bd63b656022d@avm.de>
On Tue, Mar 10, 2026 at 12:48:26PM +0100, Philipp Hahn wrote:
> While doing some static code analysis I stumbled over a common pattern,
> where IS_ERR() is combined with a NULL check. For that there is
> IS_ERR_OR_NULL().
One thing you need to check for each of these cases is whether the tests
are actually correct.
There are certainly cases amongst those that you have identified where
the check for NULL is redundant.
For example, get_phy_device() never returns NULL, yet in your netdev
patch, you have at least one instance where the return value of
get_phy_device() is checked for NULL and IS_ERR() which you then
turn into IS_ERR_OR_NULL(). Instead, the NULL check should be dropped
(as a separate patch.)
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!
^ permalink raw reply
* Re: [PATCH 38/61] net: Prefer IS_ERR_OR_NULL over manual NULL check
From: Russell King (Oracle) @ 2026-03-11 0:16 UTC (permalink / raw)
To: Philipp Hahn
Cc: amd-gfx, apparmor, bpf, ceph-devel, cocci, dm-devel, dri-devel,
gfs2, intel-gfx, intel-wired-lan, iommu, kvm, linux-arm-kernel,
linux-block, linux-bluetooth, linux-btrfs, linux-cifs, linux-clk,
linux-erofs, linux-ext4, linux-fsdevel, linux-gpio, linux-hyperv,
linux-input, linux-kernel, linux-leds, linux-media, linux-mips,
linux-mm, linux-modules, linux-mtd, linux-nfs, linux-omap,
linux-phy, linux-pm, linux-rockchip, linux-s390, linux-scsi,
linux-sctp, linux-security-module, linux-sh, linux-sound,
linux-stm32, linux-trace-kernel, linux-usb, linux-wireless,
netdev, ntfs3, samba-technical, sched-ext, target-devel,
tipc-discussion, v9fs, Igor Russkikh, Andrew Lunn,
David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni,
Pavan Chebbi, Michael Chan, Potnuri Bharat Teja, Tony Nguyen,
Przemek Kitszel, Taras Chornyi, Maxime Coquelin, Alexandre Torgue,
Iyappan Subramanian, Keyur Chudgar, Quan Nguyen, Heiner Kallweit
In-Reply-To: <20260310-b4-is_err_or_null-v1-38-bd63b656022d@avm.de>
On Tue, Mar 10, 2026 at 12:49:04PM +0100, Philipp Hahn wrote:
> diff --git a/drivers/net/mdio/mdio-xgene.c b/drivers/net/mdio/mdio-xgene.c
> index a8f91a4b7fed0927ee14e408000cd3a2bfb9b09a..09b30b563295c6085dc1358ac361301e5cf6b2a8 100644
> --- a/drivers/net/mdio/mdio-xgene.c
> +++ b/drivers/net/mdio/mdio-xgene.c
> @@ -265,7 +265,7 @@ struct phy_device *xgene_enet_phy_register(struct mii_bus *bus, int phy_addr)
> struct phy_device *phy_dev;
>
> phy_dev = get_phy_device(bus, phy_addr, false);
> - if (!phy_dev || IS_ERR(phy_dev))
> + if (IS_ERR_OR_NULL(phy_dev))
As noted in reply to your cover message, the check for NULL here is
incorrect - get_phy_device() returns either a valid pointer or an
error pointer, but never NULL.
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!
^ permalink raw reply
* [PATCH v9 0/4] ring-buffer: Making persistent ring buffers robust
From: Masami Hiramatsu (Google) @ 2026-03-11 1:32 UTC (permalink / raw)
To: Steven Rostedt
Cc: Masami Hiramatsu, Mathieu Desnoyers, linux-kernel,
linux-trace-kernel, Ian Rogers
Hi,
Here is the 9th version of improvement patches for making persistent
ring buffers robust to failures.
The previous version is here:
https://lore.kernel.org/all/177303264034.767813.5345788067082238396.stgit@mhiramat.tok.corp.google.com/
In this version, I fixed bugs/typos in [2/4][3/4] and add a bugfix patch
[1/4] and a test[4/4]. Also, add a meta->subbuf_size validation[3/4].
Thank you,
---
Masami Hiramatsu (Google) (4):
ring-buffer: Fix to update per-subbuf entries of persistent ring buffer
ring-buffer: Flush and stop persistent ring buffer on panic
ring-buffer: Skip invalid sub-buffers when validating persistent ring buffer
ring-buffer: Add persistent ring buffer selftest
arch/alpha/include/asm/Kbuild | 1
arch/arc/include/asm/Kbuild | 1
arch/arm/include/asm/Kbuild | 1
arch/arm64/include/asm/ring_buffer.h | 10 ++
arch/csky/include/asm/Kbuild | 1
arch/hexagon/include/asm/Kbuild | 1
arch/loongarch/include/asm/Kbuild | 1
arch/m68k/include/asm/Kbuild | 1
arch/microblaze/include/asm/Kbuild | 1
arch/mips/include/asm/Kbuild | 1
arch/nios2/include/asm/Kbuild | 1
arch/openrisc/include/asm/Kbuild | 1
arch/parisc/include/asm/Kbuild | 1
arch/powerpc/include/asm/Kbuild | 1
arch/riscv/include/asm/Kbuild | 1
arch/s390/include/asm/Kbuild | 1
arch/sh/include/asm/Kbuild | 1
arch/sparc/include/asm/Kbuild | 1
arch/um/include/asm/Kbuild | 1
arch/x86/include/asm/Kbuild | 1
arch/xtensa/include/asm/Kbuild | 1
include/asm-generic/ring_buffer.h | 13 +++
include/linux/ring_buffer.h | 1
kernel/trace/Kconfig | 15 +++
kernel/trace/ring_buffer.c | 169 ++++++++++++++++++++++++++--------
kernel/trace/trace.c | 4 +
26 files changed, 192 insertions(+), 40 deletions(-)
create mode 100644 arch/arm64/include/asm/ring_buffer.h
create mode 100644 include/asm-generic/ring_buffer.h
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
^ permalink raw reply
* [PATCH v9 1/4] ring-buffer: Fix to update per-subbuf entries of persistent ring buffer
From: Masami Hiramatsu (Google) @ 2026-03-11 1:32 UTC (permalink / raw)
To: Steven Rostedt
Cc: Masami Hiramatsu, Mathieu Desnoyers, linux-kernel,
linux-trace-kernel, Ian Rogers
In-Reply-To: <177319273059.130641.10882692460536780093.stgit@mhiramat.tok.corp.google.com>
From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Since the validation loop in rb_meta_validate_events() updates
the same cpu_buffer->head_page->entries, the other subbuf entries
are not updated.
Fix to use head_page to update the entries field, since it is the
cursor in this loop.
Fixes: 5f3b6e839f3c ("ring-buffer: Validate boot range memory events")
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
kernel/trace/ring_buffer.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index f16f053ef77d..353a5aa1b612 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -2053,7 +2053,7 @@ static void rb_meta_validate_events(struct ring_buffer_per_cpu *cpu_buffer)
entries += ret;
entry_bytes += local_read(&head_page->page->commit);
- local_set(&cpu_buffer->head_page->entries, ret);
+ local_set(&head_page->entries, ret);
if (head_page == cpu_buffer->commit_page)
break;
^ permalink raw reply related
* [PATCH v9 2/4] ring-buffer: Flush and stop persistent ring buffer on panic
From: Masami Hiramatsu (Google) @ 2026-03-11 1:32 UTC (permalink / raw)
To: Steven Rostedt
Cc: Masami Hiramatsu, Mathieu Desnoyers, linux-kernel,
linux-trace-kernel, Ian Rogers
In-Reply-To: <177319273059.130641.10882692460536780093.stgit@mhiramat.tok.corp.google.com>
From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
On real hardware, panic and machine reboot may not flush hardware cache
to memory. This means the persistent ring buffer, which relies on a
coherent state of memory, may not have its events written to the buffer
and they may be lost. Moreover, there may be inconsistency with the
counters which are used for validation of the integrity of the
persistent ring buffer which may cause all data to be discarded.
To avoid this issue, stop recording of the ring buffer on panic and
flush the cache of the ring buffer's memory.
Fixes: e645535a954a ("tracing: Add option to use memmapped memory for trace boot instance")
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
Changes in v9:
- Fix typo of & to &&.
- Fix typo of "Generic"
Changes in v6:
- Introduce asm/ring_buffer.h for arch_ring_buffer_flush_range().
- Use flush_cache_vmap() instead of flush_cache_all().
Changes in v5:
- Use ring_buffer_record_off() instead of ring_buffer_record_disable().
- Use flush_cache_all() to ensure flush all cache.
Changes in v3:
- update patch description.
---
arch/alpha/include/asm/Kbuild | 1 +
arch/arc/include/asm/Kbuild | 1 +
arch/arm/include/asm/Kbuild | 1 +
arch/arm64/include/asm/ring_buffer.h | 10 ++++++++++
arch/csky/include/asm/Kbuild | 1 +
arch/hexagon/include/asm/Kbuild | 1 +
arch/loongarch/include/asm/Kbuild | 1 +
arch/m68k/include/asm/Kbuild | 1 +
arch/microblaze/include/asm/Kbuild | 1 +
arch/mips/include/asm/Kbuild | 1 +
arch/nios2/include/asm/Kbuild | 1 +
arch/openrisc/include/asm/Kbuild | 1 +
arch/parisc/include/asm/Kbuild | 1 +
arch/powerpc/include/asm/Kbuild | 1 +
arch/riscv/include/asm/Kbuild | 1 +
arch/s390/include/asm/Kbuild | 1 +
arch/sh/include/asm/Kbuild | 1 +
arch/sparc/include/asm/Kbuild | 1 +
arch/um/include/asm/Kbuild | 1 +
arch/x86/include/asm/Kbuild | 1 +
arch/xtensa/include/asm/Kbuild | 1 +
include/asm-generic/ring_buffer.h | 13 +++++++++++++
kernel/trace/ring_buffer.c | 22 ++++++++++++++++++++++
23 files changed, 65 insertions(+)
create mode 100644 arch/arm64/include/asm/ring_buffer.h
create mode 100644 include/asm-generic/ring_buffer.h
diff --git a/arch/alpha/include/asm/Kbuild b/arch/alpha/include/asm/Kbuild
index 483965c5a4de..b154b4e3dfa8 100644
--- a/arch/alpha/include/asm/Kbuild
+++ b/arch/alpha/include/asm/Kbuild
@@ -5,4 +5,5 @@ generic-y += agp.h
generic-y += asm-offsets.h
generic-y += kvm_para.h
generic-y += mcs_spinlock.h
+generic-y += ring_buffer.h
generic-y += text-patching.h
diff --git a/arch/arc/include/asm/Kbuild b/arch/arc/include/asm/Kbuild
index 4c69522e0328..483caacc6988 100644
--- a/arch/arc/include/asm/Kbuild
+++ b/arch/arc/include/asm/Kbuild
@@ -5,5 +5,6 @@ generic-y += extable.h
generic-y += kvm_para.h
generic-y += mcs_spinlock.h
generic-y += parport.h
+generic-y += ring_buffer.h
generic-y += user.h
generic-y += text-patching.h
diff --git a/arch/arm/include/asm/Kbuild b/arch/arm/include/asm/Kbuild
index 03657ff8fbe3..decad5f2c826 100644
--- a/arch/arm/include/asm/Kbuild
+++ b/arch/arm/include/asm/Kbuild
@@ -3,6 +3,7 @@ generic-y += early_ioremap.h
generic-y += extable.h
generic-y += flat.h
generic-y += parport.h
+generic-y += ring_buffer.h
generated-y += mach-types.h
generated-y += unistd-nr.h
diff --git a/arch/arm64/include/asm/ring_buffer.h b/arch/arm64/include/asm/ring_buffer.h
new file mode 100644
index 000000000000..62316c406888
--- /dev/null
+++ b/arch/arm64/include/asm/ring_buffer.h
@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _ASM_ARM64_RING_BUFFER_H
+#define _ASM_ARM64_RING_BUFFER_H
+
+#include <asm/cacheflush.h>
+
+/* Flush D-cache on persistent ring buffer */
+#define arch_ring_buffer_flush_range(start, end) dcache_clean_pop(start, end)
+
+#endif /* _ASM_ARM64_RING_BUFFER_H */
diff --git a/arch/csky/include/asm/Kbuild b/arch/csky/include/asm/Kbuild
index 3a5c7f6e5aac..7dca0c6cdc84 100644
--- a/arch/csky/include/asm/Kbuild
+++ b/arch/csky/include/asm/Kbuild
@@ -9,6 +9,7 @@ generic-y += qrwlock.h
generic-y += qrwlock_types.h
generic-y += qspinlock.h
generic-y += parport.h
+generic-y += ring_buffer.h
generic-y += user.h
generic-y += vmlinux.lds.h
generic-y += text-patching.h
diff --git a/arch/hexagon/include/asm/Kbuild b/arch/hexagon/include/asm/Kbuild
index 1efa1e993d4b..0f887d4238ed 100644
--- a/arch/hexagon/include/asm/Kbuild
+++ b/arch/hexagon/include/asm/Kbuild
@@ -5,4 +5,5 @@ generic-y += extable.h
generic-y += iomap.h
generic-y += kvm_para.h
generic-y += mcs_spinlock.h
+generic-y += ring_buffer.h
generic-y += text-patching.h
diff --git a/arch/loongarch/include/asm/Kbuild b/arch/loongarch/include/asm/Kbuild
index 9034b583a88a..7e92957baf6a 100644
--- a/arch/loongarch/include/asm/Kbuild
+++ b/arch/loongarch/include/asm/Kbuild
@@ -10,5 +10,6 @@ generic-y += qrwlock.h
generic-y += user.h
generic-y += ioctl.h
generic-y += mmzone.h
+generic-y += ring_buffer.h
generic-y += statfs.h
generic-y += text-patching.h
diff --git a/arch/m68k/include/asm/Kbuild b/arch/m68k/include/asm/Kbuild
index b282e0dd8dc1..62543bf305ff 100644
--- a/arch/m68k/include/asm/Kbuild
+++ b/arch/m68k/include/asm/Kbuild
@@ -3,5 +3,6 @@ generated-y += syscall_table.h
generic-y += extable.h
generic-y += kvm_para.h
generic-y += mcs_spinlock.h
+generic-y += ring_buffer.h
generic-y += spinlock.h
generic-y += text-patching.h
diff --git a/arch/microblaze/include/asm/Kbuild b/arch/microblaze/include/asm/Kbuild
index 7178f990e8b3..0030309b47ad 100644
--- a/arch/microblaze/include/asm/Kbuild
+++ b/arch/microblaze/include/asm/Kbuild
@@ -5,6 +5,7 @@ generic-y += extable.h
generic-y += kvm_para.h
generic-y += mcs_spinlock.h
generic-y += parport.h
+generic-y += ring_buffer.h
generic-y += syscalls.h
generic-y += tlb.h
generic-y += user.h
diff --git a/arch/mips/include/asm/Kbuild b/arch/mips/include/asm/Kbuild
index 684569b2ecd6..9771c3d85074 100644
--- a/arch/mips/include/asm/Kbuild
+++ b/arch/mips/include/asm/Kbuild
@@ -12,5 +12,6 @@ generic-y += mcs_spinlock.h
generic-y += parport.h
generic-y += qrwlock.h
generic-y += qspinlock.h
+generic-y += ring_buffer.h
generic-y += user.h
generic-y += text-patching.h
diff --git a/arch/nios2/include/asm/Kbuild b/arch/nios2/include/asm/Kbuild
index 28004301c236..0a2530964413 100644
--- a/arch/nios2/include/asm/Kbuild
+++ b/arch/nios2/include/asm/Kbuild
@@ -5,6 +5,7 @@ generic-y += cmpxchg.h
generic-y += extable.h
generic-y += kvm_para.h
generic-y += mcs_spinlock.h
+generic-y += ring_buffer.h
generic-y += spinlock.h
generic-y += user.h
generic-y += text-patching.h
diff --git a/arch/openrisc/include/asm/Kbuild b/arch/openrisc/include/asm/Kbuild
index cef49d60d74c..8aa34621702d 100644
--- a/arch/openrisc/include/asm/Kbuild
+++ b/arch/openrisc/include/asm/Kbuild
@@ -8,4 +8,5 @@ generic-y += spinlock_types.h
generic-y += spinlock.h
generic-y += qrwlock_types.h
generic-y += qrwlock.h
+generic-y += ring_buffer.h
generic-y += user.h
diff --git a/arch/parisc/include/asm/Kbuild b/arch/parisc/include/asm/Kbuild
index 4fb596d94c89..d48d158f7241 100644
--- a/arch/parisc/include/asm/Kbuild
+++ b/arch/parisc/include/asm/Kbuild
@@ -4,4 +4,5 @@ generated-y += syscall_table_64.h
generic-y += agp.h
generic-y += kvm_para.h
generic-y += mcs_spinlock.h
+generic-y += ring_buffer.h
generic-y += user.h
diff --git a/arch/powerpc/include/asm/Kbuild b/arch/powerpc/include/asm/Kbuild
index 2e23533b67e3..805b5aeebb6f 100644
--- a/arch/powerpc/include/asm/Kbuild
+++ b/arch/powerpc/include/asm/Kbuild
@@ -5,4 +5,5 @@ generated-y += syscall_table_spu.h
generic-y += agp.h
generic-y += mcs_spinlock.h
generic-y += qrwlock.h
+generic-y += ring_buffer.h
generic-y += early_ioremap.h
diff --git a/arch/riscv/include/asm/Kbuild b/arch/riscv/include/asm/Kbuild
index bd5fc9403295..7721b63642f4 100644
--- a/arch/riscv/include/asm/Kbuild
+++ b/arch/riscv/include/asm/Kbuild
@@ -14,5 +14,6 @@ generic-y += ticket_spinlock.h
generic-y += qrwlock.h
generic-y += qrwlock_types.h
generic-y += qspinlock.h
+generic-y += ring_buffer.h
generic-y += user.h
generic-y += vmlinux.lds.h
diff --git a/arch/s390/include/asm/Kbuild b/arch/s390/include/asm/Kbuild
index 80bad7de7a04..0c1fc47c3ba0 100644
--- a/arch/s390/include/asm/Kbuild
+++ b/arch/s390/include/asm/Kbuild
@@ -7,3 +7,4 @@ generated-y += unistd_nr.h
generic-y += asm-offsets.h
generic-y += mcs_spinlock.h
generic-y += mmzone.h
+generic-y += ring_buffer.h
diff --git a/arch/sh/include/asm/Kbuild b/arch/sh/include/asm/Kbuild
index 4d3f10ed8275..f0403d3ee8ab 100644
--- a/arch/sh/include/asm/Kbuild
+++ b/arch/sh/include/asm/Kbuild
@@ -3,4 +3,5 @@ generated-y += syscall_table.h
generic-y += kvm_para.h
generic-y += mcs_spinlock.h
generic-y += parport.h
+generic-y += ring_buffer.h
generic-y += text-patching.h
diff --git a/arch/sparc/include/asm/Kbuild b/arch/sparc/include/asm/Kbuild
index 17ee8a273aa6..49c6bb326b75 100644
--- a/arch/sparc/include/asm/Kbuild
+++ b/arch/sparc/include/asm/Kbuild
@@ -4,4 +4,5 @@ generated-y += syscall_table_64.h
generic-y += agp.h
generic-y += kvm_para.h
generic-y += mcs_spinlock.h
+generic-y += ring_buffer.h
generic-y += text-patching.h
diff --git a/arch/um/include/asm/Kbuild b/arch/um/include/asm/Kbuild
index 1b9b82bbe322..2a1629ba8140 100644
--- a/arch/um/include/asm/Kbuild
+++ b/arch/um/include/asm/Kbuild
@@ -17,6 +17,7 @@ generic-y += module.lds.h
generic-y += parport.h
generic-y += percpu.h
generic-y += preempt.h
+generic-y += ring_buffer.h
generic-y += runtime-const.h
generic-y += softirq_stack.h
generic-y += switch_to.h
diff --git a/arch/x86/include/asm/Kbuild b/arch/x86/include/asm/Kbuild
index 4566000e15c4..078fd2c0d69d 100644
--- a/arch/x86/include/asm/Kbuild
+++ b/arch/x86/include/asm/Kbuild
@@ -14,3 +14,4 @@ generic-y += early_ioremap.h
generic-y += fprobe.h
generic-y += mcs_spinlock.h
generic-y += mmzone.h
+generic-y += ring_buffer.h
diff --git a/arch/xtensa/include/asm/Kbuild b/arch/xtensa/include/asm/Kbuild
index 13fe45dea296..e57af619263a 100644
--- a/arch/xtensa/include/asm/Kbuild
+++ b/arch/xtensa/include/asm/Kbuild
@@ -6,5 +6,6 @@ generic-y += mcs_spinlock.h
generic-y += parport.h
generic-y += qrwlock.h
generic-y += qspinlock.h
+generic-y += ring_buffer.h
generic-y += user.h
generic-y += text-patching.h
diff --git a/include/asm-generic/ring_buffer.h b/include/asm-generic/ring_buffer.h
new file mode 100644
index 000000000000..930d96571f23
--- /dev/null
+++ b/include/asm-generic/ring_buffer.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Generic arch dependent ring_buffer macros.
+ */
+#ifndef __ASM_GENERIC_RING_BUFFER_H__
+#define __ASM_GENERIC_RING_BUFFER_H__
+
+#include <linux/cacheflush.h>
+
+/* Flush cache on ring buffer range if needed */
+#define arch_ring_buffer_flush_range(start, end) flush_cache_vmap(start, end)
+
+#endif /* __ASM_GENERIC_RING_BUFFER_H__ */
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 353a5aa1b612..9f4ee9e3803d 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -6,6 +6,7 @@
*/
#include <linux/sched/isolation.h>
#include <linux/trace_recursion.h>
+#include <linux/panic_notifier.h>
#include <linux/trace_events.h>
#include <linux/ring_buffer.h>
#include <linux/trace_clock.h>
@@ -30,6 +31,7 @@
#include <linux/oom.h>
#include <linux/mm.h>
+#include <asm/ring_buffer.h>
#include <asm/local64.h>
#include <asm/local.h>
#include <asm/setup.h>
@@ -589,6 +591,7 @@ struct trace_buffer {
unsigned long range_addr_start;
unsigned long range_addr_end;
+ struct notifier_block flush_nb;
struct ring_buffer_meta *meta;
@@ -2471,6 +2474,16 @@ static void rb_free_cpu_buffer(struct ring_buffer_per_cpu *cpu_buffer)
kfree(cpu_buffer);
}
+/* Stop recording on a persistent buffer and flush cache if needed. */
+static int rb_flush_buffer_cb(struct notifier_block *nb, unsigned long event, void *data)
+{
+ struct trace_buffer *buffer = container_of(nb, struct trace_buffer, flush_nb);
+
+ ring_buffer_record_off(buffer);
+ arch_ring_buffer_flush_range(buffer->range_addr_start, buffer->range_addr_end);
+ return NOTIFY_DONE;
+}
+
static struct trace_buffer *alloc_buffer(unsigned long size, unsigned flags,
int order, unsigned long start,
unsigned long end,
@@ -2590,6 +2603,12 @@ static struct trace_buffer *alloc_buffer(unsigned long size, unsigned flags,
mutex_init(&buffer->mutex);
+ /* Persistent ring buffer needs to flush cache before reboot. */
+ if (start && end) {
+ buffer->flush_nb.notifier_call = rb_flush_buffer_cb;
+ atomic_notifier_chain_register(&panic_notifier_list, &buffer->flush_nb);
+ }
+
return_ptr(buffer);
fail_free_buffers:
@@ -2677,6 +2696,9 @@ ring_buffer_free(struct trace_buffer *buffer)
{
int cpu;
+ if (buffer->range_addr_start && buffer->range_addr_end)
+ atomic_notifier_chain_unregister(&panic_notifier_list, &buffer->flush_nb);
+
cpuhp_state_remove_instance(CPUHP_TRACE_RB_PREPARE, &buffer->node);
irq_work_sync(&buffer->irq_work.work);
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