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[146.241.238.90]) by smtp.gmail.com with ESMTPSA id az6-20020a05600c600600b0040ef04987e7sm381135wmb.16.2024.02.01.10.49.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 01 Feb 2024 10:49:24 -0800 (PST) Message-ID: <9259d368c091b071d16bd1969240f4e9dffe92fb.camel@redhat.com> Subject: Re: [PATCH net] netdevsim: avoid potential loop in nsim_dev_trap_report_work() From: Paolo Abeni To: Eric Dumazet , "David S . Miller" , Jakub Kicinski Cc: netdev@vger.kernel.org, eric.dumazet@gmail.com, syzbot , Jiri Pirko Date: Thu, 01 Feb 2024 19:49:23 +0100 In-Reply-To: <20240201175324.3752746-1-edumazet@google.com> References: <20240201175324.3752746-1-edumazet@google.com> Autocrypt: addr=pabeni@redhat.com; prefer-encrypt=mutual; keydata=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 7ZxN9ZsDL38qVIuFkSpgMZCiUHdxBC11J8nbBSLlpnc924UAyr5XrGA99 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 iWjoCy8L35zPqR5TV+f5WR5hTVCqmLHSgm1jxwKhPg9L+GfuE4d0SWd84y 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 sD2W1U7eyLdm/jCgticGDsRtweytsgCSYfbz0gdgUuL3EBYN3JLbAU+UZpy 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 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.50.3 (3.50.3-1.fc39) Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Thu, 2024-02-01 at 17:53 +0000, Eric Dumazet wrote: > Many syzbot reports include the following trace [1] >=20 > If nsim_dev_trap_report_work() can not grab the mutex, > it should rearm itself at least one jiffie later. >=20 > [1] > Sending NMI from CPU 1 to CPUs 0: > NMI backtrace for cpu 0 > CPU: 0 PID: 32383 Comm: kworker/0:2 Not tainted 6.8.0-rc2-syzkaller-00031= -g861c0981648f #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS G= oogle 11/17/2023 > Workqueue: events nsim_dev_trap_report_work > RIP: 0010:bytes_is_nonzero mm/kasan/generic.c:89 [inline] > RIP: 0010:memory_is_nonzero mm/kasan/generic.c:104 [inline] > RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:129 [inline] > RIP: 0010:memory_is_poisoned mm/kasan/generic.c:161 [inline] > RIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline] > RIP: 0010:kasan_check_range+0x101/0x190 mm/kasan/generic.c:189 > Code: 07 49 39 d1 75 0a 45 3a 11 b8 01 00 00 00 7c 0b 44 89 c2 e8 21 ed f= f ff 83 f0 01 5b 5d 41 5c c3 48 85 d2 74 4f 48 01 ea eb 09 <48> 83 c0 01 48= 39 d0 74 41 80 38 00 74 f2 eb b6 41 bc 08 00 00 00 > RSP: 0018:ffffc90012dcf998 EFLAGS: 00000046 > RAX: fffffbfff258af1e RBX: fffffbfff258af1f RCX: ffffffff8168eda3 > RDX: fffffbfff258af1f RSI: 0000000000000004 RDI: ffffffff92c578f0 > RBP: fffffbfff258af1e R08: 0000000000000000 R09: fffffbfff258af1e > R10: ffffffff92c578f3 R11: ffffffff8acbcbc0 R12: 0000000000000002 > R13: ffff88806db38400 R14: 1ffff920025b9f42 R15: ffffffff92c578e8 > FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000= 000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 000000c00994e078 CR3: 000000002c250000 CR4: 00000000003506f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > > > > instrument_atomic_read include/linux/instrumented.h:68 [inline] > atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline] > queued_spin_is_locked include/asm-generic/qspinlock.h:57 [inline] > debug_spin_unlock kernel/locking/spinlock_debug.c:101 [inline] > do_raw_spin_unlock+0x53/0x230 kernel/locking/spinlock_debug.c:141 > __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:150 [inli= ne] > _raw_spin_unlock_irqrestore+0x22/0x70 kernel/locking/spinlock.c:194 > debug_object_activate+0x349/0x540 lib/debugobjects.c:726 > debug_work_activate kernel/workqueue.c:578 [inline] > insert_work+0x30/0x230 kernel/workqueue.c:1650 > __queue_work+0x62e/0x11d0 kernel/workqueue.c:1802 > __queue_delayed_work+0x1bf/0x270 kernel/workqueue.c:1953 > queue_delayed_work_on+0x106/0x130 kernel/workqueue.c:1989 > queue_delayed_work include/linux/workqueue.h:563 [inline] > schedule_delayed_work include/linux/workqueue.h:677 [inline] > nsim_dev_trap_report_work+0x9c0/0xc80 drivers/net/netdevsim/dev.c:842 > process_one_work+0x886/0x15d0 kernel/workqueue.c:2633 > process_scheduled_works kernel/workqueue.c:2706 [inline] > worker_thread+0x8b9/0x1290 kernel/workqueue.c:2787 > kthread+0x2c6/0x3a0 kernel/kthread.c:388 > ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 > ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242 > >=20 > Fixes: 012ec02ae441 ("netdevsim: convert driver to use unlocked devlink A= PI during init/fini") > Reported-by: syzbot > Signed-off-by: Eric Dumazet > Cc: Jiri Pirko > --- > drivers/net/netdevsim/dev.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) >=20 > diff --git a/drivers/net/netdevsim/dev.c b/drivers/net/netdevsim/dev.c > index b4d3b9cde8bd685202f135cf9c845d1be76ef428..92a7a36b93ac0cc1b02a551b9= 74fb390254ac484 100644 > --- a/drivers/net/netdevsim/dev.c > +++ b/drivers/net/netdevsim/dev.c > @@ -835,14 +835,14 @@ static void nsim_dev_trap_report_work(struct work_s= truct *work) > trap_report_dw.work); > nsim_dev =3D nsim_trap_data->nsim_dev; > =20 > - /* For each running port and enabled packet trap, generate a UDP > - * packet with a random 5-tuple and report it. > - */ > if (!devl_trylock(priv_to_devlink(nsim_dev))) { > - schedule_delayed_work(&nsim_dev->trap_data->trap_report_dw, 0); > + schedule_delayed_work(&nsim_dev->trap_data->trap_report_dw, 1); The patch LGTM, thanks! I'm wondering if we have a similar problem in devlink_rel_nested_in_notify_work(): if (!devl_trylock(devlink)) { devlink_put(devlink); goto reschedule_work; } //... reschedule_work: schedule_work(&rel->nested_in.notify_work); And possibly adding 1ms delay there could be problematic? Cheers, Paolo