From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2ED3BCD1292 for ; Thu, 4 Apr 2024 15:18:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:References:To:From:Subject: Cc:Message-Id:Date:Mime-Version:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Z1ET9/iEdqKFpL/E55cw8Obw5OIWdgpmf6DVSm11co8=; b=CBR9zp9hyEnS8X tp2sB058Je4a+ny7bnDMGdgM0t/Js4xhtdyIUJxQc0E/GvRQ2gWq5nl8u3hH1ApwZeZtfCKYUjYqj eC73t0ICBwXjRVhAl6175npVZPzmb9vI1PO9FQG1053hvAMa/58Ym8l+uqx/MpHu6wPvTTv3gVlF2 zqP0EYNSPpKx7k8yDR7zaubfaPNZojLkhDHvsvDpMqAZTlx9uw1lD89IKxaMWCdc1n8hIXRfD/PfT /DGJ12HbUNlHB3BpIOtmgL52uXzt/SxJerXYP0OlQpMJqc9sSu41mvj5uFNsdN7QQkq4bn4882W60 TCi84EpsrZFNxmkAaSAQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rsOrH-00000003Cr7-1XBK; Thu, 04 Apr 2024 15:18:31 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rsOrE-00000003CpV-1EYO for linux-arm-kernel@lists.infradead.org; Thu, 04 Apr 2024 15:18:29 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 0EFAA6171D; Thu, 4 Apr 2024 15:18:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 20D27C433F1; Thu, 4 Apr 2024 15:18:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1712243905; bh=TvEvr9FBUdBPzVIz7Xo6925tGz3ksxrEHjA3jd2o6gQ=; h=Date:Cc:Subject:From:To:References:In-Reply-To:From; b=uc+eKnYDHQCarh9ior1695h4dE8Q7VytiZ1RR23OVgkk18QX/uj6Yy2UUmf40vdGH uHWh47+peHOH+5RwcmI79d1rfyQ1YJfWxtoJ5NsgciMNxgASFbuTMWjoPw2JIdgEzr tKlBr7GvDo/3LM2Q8T5MWua0k8+ZuA9NeZEM9MTjjo19FLHblDcwW9+C8aFZGm/Erv 8EbaHK9katpUacGJc5D2nO/VwjD5y0kJlyI0InTABF6knrQONAguHJUxQ73hFRv8SU hK7C0ngToMUmHUJ+aN6BBnpTvxJU6tYx2NppOg8Fn7gwTR8W88MIbsCjSElXNbIO7Q Y3oPToKH7ViZQ== Mime-Version: 1.0 Date: Thu, 04 Apr 2024 18:18:21 +0300 Message-Id: Cc: , , , , , , , , , Subject: Re: [PATCH v2 4/4] kprobes: Remove core dependency on modules From: "Jarkko Sakkinen" To: "Jarkko Sakkinen" , "Mark Rutland" , X-Mailer: aerc 0.17.0 References: <20240403150154.667649-1-mark.rutland@arm.com> <20240403150154.667649-5-mark.rutland@arm.com> In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240404_081828_462715_34DA19FE X-CRM114-Status: GOOD ( 35.39 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu Apr 4, 2024 at 11:15 AM EEST, Jarkko Sakkinen wrote: > On Wed Apr 3, 2024 at 6:01 PM EEST, Mark Rutland wrote: > > From: Jarkko Sakkinen > > > > Tracing with kprobes while running a monolithic kernel is currently > > impossible because KPROBES depends on MODULES. While this dependency is > > necessary when HAVE_KPROBES_ALLOC=n and the core kprobes code allocates > > memory using module_alloc(), all the other module-specific code only > > exist to handle the case when MODULES=y, and can be hidden behind > > ifdeffery. > > > > Add the necessary ifdeffery, and remove the dependency on MODULES=y when > > HAVE_KPROBES_ALLOC=y. > > > > As of this patch kprobes can be used when MODULES=n on arm64 and > > riscv. All other architectures still depend on MODULES, either by virtue > > of the core dependency on MODULES when HAVE_KPROBES_ALLOC=n, or by > > virtue of an explciit dependency on MODULES in arch code. > > > > Other architectures can enable support by implementing their own > > kprobes_alloc_insn_page() and kprobes_free_insn_page() which do not > > depend on MODULES. > > > > Signed-off-by: Jarkko Sakkinen > > Link: https://lore.kernel.org/lkml/20240326134616.7691-1-jarkko@kernel.org/ > > [Mark: Remove execmem changes, depend on HAVE_KPROBES_ALLOC] > > Signed-off-by: Mark Rutland > > Cc: Albert Ou > > Cc: Anil S Keshavamurthy > > Cc: Catalin Marinas > > Cc: David S. Miller > > Cc: Jarkko Sakkinen > > Cc: Masami Hiramatsu > > Cc: Naveen N. Rao > > Cc: Palmer Dabbelt > > Cc: Paul Walmsley > > Cc: Will Deacon > > --- > > arch/Kconfig | 2 +- > > kernel/kprobes.c | 46 ++++++++++++++++++++++--------------- > > kernel/trace/trace_kprobe.c | 15 ++++++++++-- > > 3 files changed, 41 insertions(+), 22 deletions(-) > > > > diff --git a/arch/Kconfig b/arch/Kconfig > > index 85bb59f7b8c07..0df2c88547b3c 100644 > > --- a/arch/Kconfig > > +++ b/arch/Kconfig > > @@ -52,7 +52,7 @@ config GENERIC_ENTRY > > > > config KPROBES > > bool "Kprobes" > > - depends on MODULES > > + depends on MODULES || HAVE_KPROBES_ALLOC > > depends on HAVE_KPROBES > > select KALLSYMS > > select TASKS_RCU if PREEMPTION > > diff --git a/kernel/kprobes.c b/kernel/kprobes.c > > index fa2ee4e59eca2..ec4493a41b505 100644 > > --- a/kernel/kprobes.c > > +++ b/kernel/kprobes.c > > @@ -1594,6 +1594,7 @@ static int check_kprobe_address_safe(struct kprobe *p, > > goto out; > > } > > > > +#ifdef CONFIG_MODULES > > /* > > * If the module freed '.init.text', we couldn't insert > > * kprobes in there. > > @@ -1604,7 +1605,9 @@ static int check_kprobe_address_safe(struct kprobe *p, > > *probed_mod = NULL; > > ret = -ENOENT; > > } > > +#endif /* CONFIG_MODULES */ > > } > > + > > out: > > preempt_enable(); > > jump_label_unlock(); > > @@ -2484,24 +2487,6 @@ int kprobe_add_area_blacklist(unsigned long start, unsigned long end) > > return 0; > > } > > > > -/* Remove all symbols in given area from kprobe blacklist */ > > -static void kprobe_remove_area_blacklist(unsigned long start, unsigned long end) > > -{ > > - struct kprobe_blacklist_entry *ent, *n; > > - > > - list_for_each_entry_safe(ent, n, &kprobe_blacklist, list) { > > - if (ent->start_addr < start || ent->start_addr >= end) > > - continue; > > - list_del(&ent->list); > > - kfree(ent); > > - } > > -} > > - > > -static void kprobe_remove_ksym_blacklist(unsigned long entry) > > -{ > > - kprobe_remove_area_blacklist(entry, entry + 1); > > -} > > - > > int __weak arch_kprobe_get_kallsym(unsigned int *symnum, unsigned long *value, > > char *type, char *sym) > > { > > @@ -2566,6 +2551,25 @@ static int __init populate_kprobe_blacklist(unsigned long *start, > > return ret ? : arch_populate_kprobe_blacklist(); > > } > > > > +#ifdef CONFIG_MODULES > > +/* Remove all symbols in given area from kprobe blacklist */ > > +static void kprobe_remove_area_blacklist(unsigned long start, unsigned long end) > > +{ > > + struct kprobe_blacklist_entry *ent, *n; > > + > > + list_for_each_entry_safe(ent, n, &kprobe_blacklist, list) { > > + if (ent->start_addr < start || ent->start_addr >= end) > > + continue; > > + list_del(&ent->list); > > + kfree(ent); > > + } > > +} > > + > > +static void kprobe_remove_ksym_blacklist(unsigned long entry) > > +{ > > + kprobe_remove_area_blacklist(entry, entry + 1); > > +} > > + > > static void add_module_kprobe_blacklist(struct module *mod) > > { > > unsigned long start, end; > > @@ -2662,6 +2666,9 @@ static int kprobes_module_callback(struct notifier_block *nb, > > mutex_unlock(&kprobe_mutex); > > return NOTIFY_DONE; > > } > > +#else > > +#define kprobes_module_callback (NULL) > > +#endif /* CONFIG_MODULES */ > > > > static struct notifier_block kprobe_module_nb = { > > .notifier_call = kprobes_module_callback, > > @@ -2726,7 +2733,8 @@ static int __init init_kprobes(void) > > err = arch_init_kprobes(); > > if (!err) > > err = register_die_notifier(&kprobe_exceptions_nb); > > - if (!err) > > + > > + if (!err && IS_ENABLED(CONFIG_MODULES)) > > err = register_module_notifier(&kprobe_module_nb); > > > > kprobes_initialized = (err == 0); > > diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c > > index 14099cc17fc9e..c509ba776e679 100644 > > --- a/kernel/trace/trace_kprobe.c > > +++ b/kernel/trace/trace_kprobe.c > > @@ -111,6 +111,7 @@ static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk, > > return strncmp(module_name(mod), name, len) == 0 && name[len] == ':'; > > } > > > > +#ifdef CONFIG_MODULES > > static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk) > > { > > char *p; > > @@ -129,6 +130,9 @@ static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk) > > > > return ret; > > } > > +#else > > +#define trace_kprobe_module_exist(tk) false /* aka a module never exists */ > > +#endif /* CONFIG_MODULES */ > > > > static bool trace_kprobe_is_busy(struct dyn_event *ev) > > { > > @@ -670,6 +674,7 @@ static int register_trace_kprobe(struct trace_kprobe *tk) > > return ret; > > } > > > > +#ifdef CONFIG_MODULES > > /* Module notifier call back, checking event on the module */ > > static int trace_kprobe_module_callback(struct notifier_block *nb, > > unsigned long val, void *data) > > @@ -699,6 +704,9 @@ static int trace_kprobe_module_callback(struct notifier_block *nb, > > > > return NOTIFY_DONE; > > } > > +#else > > +#define trace_kprobe_module_callback (NULL) > > +#endif /* CONFIG_MODULES */ > > > > static struct notifier_block trace_kprobe_module_nb = { > > .notifier_call = trace_kprobe_module_callback, > > @@ -1933,8 +1941,11 @@ static __init int init_kprobe_trace_early(void) > > if (ret) > > return ret; > > > > - if (register_module_notifier(&trace_kprobe_module_nb)) > > - return -EINVAL; > > + if (IS_ENABLED(CONFIG_MODULES)) { > > + ret = register_module_notifier(&trace_kprobe_module_nb); > > + if (ret) > > + return -EINVAL; > > + } > > > > return 0; > > } > > 2/4, 3/4, 4/4: > > Tested-by: Jarkko Sakkinen # arch/riscv Hey, I tried the pci_proc_init example: [ 3.060703] ------------[ ftrace bug ]------------ [ 3.060944] ftrace faulted on writing [ 3.060987] [] pci_proc_init+0x0/0x80 [ 3.061509] Updating ftrace call site to call a different ftrace function [ 3.061756] ftrace record flags: 80100001 [ 3.061925] (1) [ 3.061925] expected tramp: ffffffff8000aa60 [ 3.062527] ------------[ cut here ]------------ [ 3.062652] WARNING: CPU: 0 PID: 18 at kernel/trace/ftrace.c:2180 ftrace_bug+0x282/0x2b8 [ 3.062747] CPU: 0 PID: 18 Comm: migration/0 Not tainted 6.9.0-rc1 #2 [ 3.062807] Hardware name: riscv-virtio,qemu (DT) [ 3.062868] Stopper: multi_cpu_stop+0x0/0x1a0 <- stop_machine_cpuslocked+0x140/0x18c [ 3.062925] epc : ftrace_bug+0x282/0x2b8 [ 3.062957] ra : ftrace_bug+0x282/0x2b8 [ 3.062989] epc : ffffffff80fc31f4 ra : ffffffff80fc31f4 sp : ff20000000093c70 [ 3.063014] gp : ffffffff824b7780 tp : ff60000002a85940 t0 : ffffffff800923a6 [ 3.063037] t1 : 0000000000000020 t2 : 6465746365707865 s0 : ff20000000093cb0 [ 3.063061] s1 : ffffffff8102c0da a0 : 0000000000000022 a1 : ffffffff8229b7f0 [ 3.063084] a2 : 0000000000000010 a3 : fffffffffffffffe a4 : 0000000000000000 [ 3.063108] a5 : 0000000000000000 a6 : 0000000000000000 a7 : 0000000000000001 [ 3.063131] s2 : ff60000002850ab0 s3 : ffffffffffffffff s4 : 0000000000000002 [ 3.063154] s5 : 0000000002000000 s6 : 0000000082000000 s7 : 0000000000000000 [ 3.063178] s8 : 0000000000000001 s9 : ffffffff824bca18 s10: ff60000002845140 [ 3.063202] s11: 00000000000000ab t3 : ffffffff824ce9ef t4 : ffffffff824ce9ef [ 3.063225] t5 : ffffffff824ce9f0 t6 : ff20000000093aa8 [ 3.063248] status: 0000000200000100 badaddr: 0000000000000000 cause: 0000000000000003 [ 3.063331] [] ftrace_bug+0x282/0x2b8 [ 3.063398] [] ftrace_replace_code+0xfe/0x168 [ 3.063430] [] ftrace_modify_all_code+0x5c/0x16a [ 3.063460] [] __ftrace_modify_code+0x12/0x1c [ 3.063490] [] multi_cpu_stop+0x118/0x1a0 [ 3.063519] [] cpu_stopper_thread+0xb2/0x12a [ 3.063548] [] smpboot_thread_fn+0x1aa/0x1d2 [ 3.063577] [] kthread+0xfe/0x106 [ 3.063606] [] ret_from_fork+0xe/0x20 [ 3.063676] ---[ end trace 0000000000000000 ]--- [ 3.069730] ------------[ cut here ]------------ [ 3.069861] Failed to disarm kprobe-ftrace at pci_proc_init+0x0/0x80 (error -19) [ 3.070078] WARNING: CPU: 0 PID: 1 at kernel/kprobes.c:1128 __disarm_kprobe_ftrace+0x9a/0xae [ 3.070124] CPU: 0 PID: 1 Comm: swapper/0 Tainted: G W 6.9.0-rc1 #2 [ 3.070133] Hardware name: riscv-virtio,qemu (DT) [ 3.070141] epc : __disarm_kprobe_ftrace+0x9a/0xae [ 3.070150] ra : __disarm_kprobe_ftrace+0x9a/0xae [ 3.070157] epc : ffffffff800ffcda ra : ffffffff800ffcda sp : ff2000000000be30 [ 3.070162] gp : ffffffff824b7780 tp : ff60000002a70000 t0 : ffffffff800923a6 [ 3.070167] t1 : 0000000000000046 t2 : 6f742064656c6961 s0 : ff2000000000be60 [ 3.070173] s1 : ffffffffffffffed a0 : 0000000000000044 a1 : ffffffff8229b7f0 [ 3.070178] a2 : 0000000000000010 a3 : fffffffffffffffe a4 : 0000000000000000 [ 3.070182] a5 : 0000000000000000 a6 : 0000000000000000 a7 : 0000000000000001 [ 3.070187] s2 : ffffffff824bc940 s3 : ffffffff822ac158 s4 : ff60000002b53c80 [ 3.070192] s5 : ffffffff824bc940 s6 : ffffffff822ac158 s7 : ffffffff81000000 [ 3.070197] s8 : ffffffff814775f8 s9 : ffffffff824f23d8 s10: 0000000000000000 [ 3.070202] s11: 0000000000000000 t3 : ffffffff824ce9d7 t4 : ffffffff824ce9d7 [ 3.070206] t5 : ffffffff824ce9d8 t6 : ff2000000000bc48 [ 3.070211] status: 0000000200000120 badaddr: 0000000000000000 cause: 0000000000000003 [ 3.070218] [] __disarm_kprobe_ftrace+0x9a/0xae [ 3.070228] [] kprobe_free_init_mem+0xc2/0x130 [ 3.070236] [] kernel_init+0x46/0x14e [ 3.070245] [] ret_from_fork+0xe/0x20 [ 3.070254] ---[ end trace 0000000000000000 ]--- [ This is with riscv64 defconfig, tracing shenanigans and the following bootconfig and the bug was realized in QEMU: ftrace { tracing_on = 0 tracer = "function_graph" event { kprobes.pci_proc_init_begin { probes = "pci_proc_init" actions = "traceon" } kprobes.pci_proc_init_end { probes = "pci_proc_init%return" actions = "traceoff" } } } kernel { console = hvc0 dyndbg = "file arch/riscv/kernel/* +p" earlycon = sbi memblock = debug memtest = 1 tp_printk frace_dump_on_oops } BR, Jarkko _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel