From: "Coelho, Luciano" <luciano.coelho@intel.com>
To: "jikos@kernel.org" <jikos@kernel.org>,
"johannes@sipsolutions.net" <johannes@sipsolutions.net>,
"kvalo@codeaurora.org" <kvalo@codeaurora.org>
Cc: "linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>,
"hkallweit1@gmail.com" <hkallweit1@gmail.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] iwlwifi: don't call netif_napi_add() with rxq->lock held (was Re: Lockdep warning in iwl_pcie_rx_handle())
Date: Tue, 2 Mar 2021 10:49:51 +0000 [thread overview]
Message-ID: <7de7aa19e5ea8a856cce4193ebb3c31b4ef78ca7.camel@intel.com> (raw)
In-Reply-To: <nycvar.YFH.7.76.2103021134060.12405@cbobk.fhfr.pm>
On Tue, 2021-03-02 at 11:34 +0100, Jiri Kosina wrote:
> From: Jiri Kosina <jkosina@suse.cz>
>
> We can't call netif_napi_add() with rxq-lock held, as there is a potential
> for deadlock as spotted by lockdep (see below). rxq->lock is not
> protecting anything over the netif_napi_add() codepath anyway, so let's
> drop it just before calling into NAPI.
>
> ========================================================
> WARNING: possible irq lock inversion dependency detected
> 5.12.0-rc1-00002-gbada49429032 #5 Not tainted
> --------------------------------------------------------
> irq/136-iwlwifi/565 just changed the state of lock:
> ffff89f28433b0b0 (&rxq->lock){+.-.}-{2:2}, at: iwl_pcie_rx_handle+0x7f/0x960 [iwlwifi]
> but this lock took another, SOFTIRQ-unsafe lock in the past:
> (napi_hash_lock){+.+.}-{2:2}
>
> and interrupts could create inverse lock ordering between them.
>
> other info that might help us debug this:
> Possible interrupt unsafe locking scenario:
>
> CPU0 CPU1
> ---- ----
> lock(napi_hash_lock);
> local_irq_disable();
> lock(&rxq->lock);
> lock(napi_hash_lock);
> <Interrupt>
> lock(&rxq->lock);
>
> *** DEADLOCK ***
>
> 1 lock held by irq/136-iwlwifi/565:
> #0: ffff89f2b1440170 (sync_cmd_lockdep_map){+.+.}-{0:0}, at: iwl_pcie_irq_handler+0x5/0xb30
>
> the shortest dependencies between 2nd lock and 1st lock:
> -> (napi_hash_lock){+.+.}-{2:2} {
> HARDIRQ-ON-W at:
> lock_acquire+0x277/0x3d0
> _raw_spin_lock+0x2c/0x40
> netif_napi_add+0x14b/0x270
> e1000_probe+0x2fe/0xee0 [e1000e]
> local_pci_probe+0x42/0x90
> pci_device_probe+0x10b/0x1c0
> really_probe+0xef/0x4b0
> driver_probe_device+0xde/0x150
> device_driver_attach+0x4f/0x60
> __driver_attach+0x9c/0x140
> bus_for_each_dev+0x79/0xc0
> bus_add_driver+0x18d/0x220
> driver_register+0x5b/0xf0
> do_one_initcall+0x5b/0x300
> do_init_module+0x5b/0x21c
> load_module+0x1dae/0x22c0
> __do_sys_finit_module+0xad/0x110
> do_syscall_64+0x33/0x80
> entry_SYSCALL_64_after_hwframe+0x44/0xae
> SOFTIRQ-ON-W at:
> lock_acquire+0x277/0x3d0
> _raw_spin_lock+0x2c/0x40
> netif_napi_add+0x14b/0x270
> e1000_probe+0x2fe/0xee0 [e1000e]
> local_pci_probe+0x42/0x90
> pci_device_probe+0x10b/0x1c0
> really_probe+0xef/0x4b0
> driver_probe_device+0xde/0x150
> device_driver_attach+0x4f/0x60
> __driver_attach+0x9c/0x140
> bus_for_each_dev+0x79/0xc0
> bus_add_driver+0x18d/0x220
> driver_register+0x5b/0xf0
> do_one_initcall+0x5b/0x300
> do_init_module+0x5b/0x21c
> load_module+0x1dae/0x22c0
> __do_sys_finit_module+0xad/0x110
> do_syscall_64+0x33/0x80
> entry_SYSCALL_64_after_hwframe+0x44/0xae
> INITIAL USE at:
> lock_acquire+0x277/0x3d0
> _raw_spin_lock+0x2c/0x40
> netif_napi_add+0x14b/0x270
> e1000_probe+0x2fe/0xee0 [e1000e]
> local_pci_probe+0x42/0x90
> pci_device_probe+0x10b/0x1c0
> really_probe+0xef/0x4b0
> driver_probe_device+0xde/0x150
> device_driver_attach+0x4f/0x60
> __driver_attach+0x9c/0x140
> bus_for_each_dev+0x79/0xc0
> bus_add_driver+0x18d/0x220
> driver_register+0x5b/0xf0
> do_one_initcall+0x5b/0x300
> do_init_module+0x5b/0x21c
> load_module+0x1dae/0x22c0
> __do_sys_finit_module+0xad/0x110
> do_syscall_64+0x33/0x80
> entry_SYSCALL_64_after_hwframe+0x44/0xae
> }
> ... key at: [<ffffffffae84ef38>] napi_hash_lock+0x18/0x40
> ... acquired at:
> _raw_spin_lock+0x2c/0x40
> netif_napi_add+0x14b/0x270
> _iwl_pcie_rx_init+0x1f4/0x710 [iwlwifi]
> iwl_pcie_rx_init+0x1b/0x3b0 [iwlwifi]
> iwl_trans_pcie_start_fw+0x2ac/0x6a0 [iwlwifi]
> iwl_mvm_load_ucode_wait_alive+0x116/0x460 [iwlmvm]
> iwl_run_init_mvm_ucode+0xa4/0x3a0 [iwlmvm]
> iwl_op_mode_mvm_start+0x9ed/0xbf0 [iwlmvm]
> _iwl_op_mode_start.isra.4+0x42/0x80 [iwlwifi]
> iwl_opmode_register+0x71/0xe0 [iwlwifi]
> iwl_mvm_init+0x34/0x1000 [iwlmvm]
> do_one_initcall+0x5b/0x300
> do_init_module+0x5b/0x21c
> load_module+0x1dae/0x22c0
> __do_sys_finit_module+0xad/0x110
> do_syscall_64+0x33/0x80
> entry_SYSCALL_64_after_hwframe+0x44/0xae
>
> [ ... lockdep output trimmed .... ]
>
> Fixes: 25edc8f259c7106 ("iwlwifi: pcie: properly implement NAPI")
> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
> ---
>
> v1->v2: Previous patch was not refreshed against current code-base, sorry.
>
> drivers/net/wireless/intel/iwlwifi/pcie/rx.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
Thanks, Jiri! Let's take your patch since you already sent it out.
Kalle, can you please take this directly to wireless-drivers.git?
Acked-by: Luca Coelho <luciano.coelho@intel.com>
--
Cheers,
Luca.
next prev parent reply other threads:[~2021-03-02 11:02 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-01 20:44 Lockdep warning in iwl_pcie_rx_handle() Jiri Kosina
2021-03-01 21:09 ` Jiri Kosina
2021-03-01 21:12 ` Johannes Berg
2021-03-02 9:27 ` [PATCH] iwlwifi: don't call netif_napi_add() with rxq->lock held (was Re: Lockdep warning in iwl_pcie_rx_handle()) Jiri Kosina
2021-03-02 10:34 ` [PATCH v2] " Jiri Kosina
2021-03-02 10:49 ` Coelho, Luciano [this message]
2021-03-02 12:17 ` Kalle Valo
2021-03-02 14:55 ` Jiri Kosina
2021-03-03 21:39 ` Sedat Dilek
2021-03-03 15:59 ` Kalle Valo
[not found] ` <20210303155941.25521C43463@smtp.codeaurora.org>
2021-03-03 18:01 ` Jiri Kosina
2021-03-03 18:33 ` Kalle Valo
2021-03-03 19:19 ` Jiri Kosina
2021-03-02 10:48 ` [PATCH] " Coelho, Luciano
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