Re: vhost_dev_cleanup() crash: BUG: unable to handle kernel NULLpointer dereference
From: Eric Dumazet
Date: Tue Aug 31 2010 - 06:50:18 EST
Le mardi 31 aoÃt 2010 Ã 09:57 +0200, Ingo Molnar a Ãcrit :
> FYI, there's a new crash in the vnet driver that occasionally triggers
> on ordinary host bootups as well, when (non-virtualized) networking
> initializes:
>
> [ 86.563889] [<ffffffff81b05655>] page_fault+0x25/0x30
> [ 86.569065] [<ffffffff8186d899>] ? vhost_poll_flush+0x11a/0x156
> [ 86.575119] [<ffffffff8105f511>] ? kthread_stop+0xa/0x57
> [ 86.580544] [<ffffffff8186e535>] vhost_dev_cleanup+0x269/0x271
> [ 86.586528] [<ffffffff8186e974>] vhost_net_release+0x48/0x7f
> [ 86.592359] [<ffffffff810c5419>] fput+0x120/0x1d4
> [ 86.597185] [<ffffffff810c2a1d>] filp_close+0x63/0x6d
> [ 86.602353] [<ffffffff810c2acf>] sys_close+0xa8/0xe2
> [ 86.607429] [<ffffffff81008602>] system_call_fastpath+0x16/0x1b
>
> See the full crashlog below. Config attached.
>
> AFAICT this bug probably went upstream during the merge window.
>
> Thanks,
>
> Ingo
>
> [ 86.262123] BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
> [ 86.265200] IP:ntry for device- [<ffffffff8105f511>] kthread_stop+0xa/0x57
> [ 86.265200] PGD 3ad75067 PUD 3b352067 PMD 0
> [ 86.265200] Oops: 0002 [#1] SMP
> [ 86.265200] last sysfs file: /sys/devices/pnp0/00:0d/id
> [ 86.265200] CPU 0 mapper found
> Is
> [ 86.265200] Pid: 1254, comm: multipath.stati Not tainted 2.6.36-rc3-tip+ #31158 A8N-E/System Product Name
> device-mapper d[ 86.265200] RIP: 0010:[<ffffffff8105f511>] [<ffffffff8105f511>] kthread_stop+0xa/0x57
> river missing fr[ 86.265200] RSP: 0018:ffff88003ae83e58 EFLAGS: 00010246
> [ 86.265200] RAX: ffff88003d1dc170 RBX: 0000000000000000 RCX: 0000000000000000
> [ 86.265200] RDX: ffff88003aa82030 RSI: 0000000000000001 RDI: 0000000000000000
> om kernel?
> devi[ 86.265200] RBP: ffff88003ae83e68 R08: ffff88003ae83e68 R09: 0000000000000001
> [ 86.265200] R10: ffffffff8186d899 R11: 0000000000000246 R12: ffff88003d1dc8f0
> [ 86.265200] R13: 0000000000000002 R14: ffff88003b2a1000 R15: ffff88003aa82030
> [ 86.265200] FS: 0000000001fc5880(0063) GS:ffff88003fc00000(0000) knlGS:0000000000000000
> ce-mapper: versi[ 86.265200] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
> [ 86.265200] CR2: 0000000000000010 CR3: 000000003b377000 CR4: 00000000000006f0
> on ioctl failed:[ 86.265200] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [ 86.265200] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> [ 86.265200] Process multipath.stati (pid: 1254, threadinfo ffff88003ae82000, task ffff88003b3e8000)
> [ 86.265200] Stack:
> [ 86.265200] ffff88003d1dc090 ffff88003d1dc8f0 ffff88003ae83e98 ffffffff8186e535
> [ 86.265200] <0> ffff88003ae83e98 ffff88003d1dc090 0000000000000000 0000000000000000
> [ 86.265200] <0> ffff88003ae83ec8 ffffffff8186e974 0000000000000008 ffff88003b3a6180
> [ 86.265200] Call Trace:
> [ 86.265200] [<ffffffff8186e535>] vhost_dev_cleanup+0x269/0x271
> Operation not p[ 86.265200] [<ffffffff8186e974>] vhost_net_release+0x48/0x7f
> [ 86.265200] [<ffffffff810c5419>] fput+0x120/0x1d4
> ermitted
> [ 86.265200] [<ffffffff810c2a1d>] filp_close+0x63/0x6d
> [ 86.265200] [<ffffffff810c2acf>] sys_close+0xa8/0xe2
> [ 86.265200] [<ffffffff81008602>] system_call_fastpath+0x16/0x1b
> [ 86.265200] Code: 4c 8b 25 83 b4 16 01 49 81 fc 70 a9 1c 82 75 94 48 c7 c7 80 a9 1c 82 e8 99 5b aa 00 e9 50 ff ff ff 55 48 89 e5 41 54 53 48 89 fb <f0> ff 47 10 4c 8b a7 00 05 00 00 48 83 bf 00 05 00 00 00 74 16
> [ 86.265200] RIP [<ffffffff8105f511>] kthread_stop+0xa/0x57
> [ 86.265200] RSP <ffff88003ae83e58>
> [ 86.265200] CR2: 0000000000000010
> [ 86.499743] ---[ end trace 433623c38ffeb225 ]---
> [ 86.504397] Kernel panic - not syncing: Fatal exception
> [ 86.509633] Pid: 1254, comm: multipath.stati Tainted: G D 2.6.36-rc3-tip+ #31158
> [ 86.517858] Call Trace:
> [ 86.520343] [<ffffffff81b01c87>] panic+0x8c/0x196
> [ 86.525181] [<ffffffff81048405>] ? kmsg_dump+0x126/0x140
> [ 86.530606] [<ffffffff8100c43d>] oops_end+0x8f/0x9c
> [ 86.535611] [<ffffffff8102d93d>] no_context+0x1f7/0x206
> [ 86.540948] [<ffffffff8102dacb>] __bad_area_nosemaphore+0x17f/0x1a2
> [ 86.547334] [<ffffffff8102db40>] bad_area+0x42/0x49
> [ 86.552329] [<ffffffff8102de84>] do_page_fault+0x1fe/0x363
> [ 86.557925] [<ffffffff81352dff>] ? do_raw_spin_lock+0x6b/0x122
> [ 86.563889] [<ffffffff81b05655>] page_fault+0x25/0x30
> [ 86.569065] [<ffffffff8186d899>] ? vhost_poll_flush+0x11a/0x156
> [ 86.575119] [<ffffffff8105f511>] ? kthread_stop+0xa/0x57
> [ 86.580544] [<ffffffff8186e535>] vhost_dev_cleanup+0x269/0x271
> [ 86.586528] [<ffffffff8186e974>] vhost_net_release+0x48/0x7f
> [ 86.592359] [<ffffffff810c5419>] fput+0x120/0x1d4
> [ 86.597185] [<ffffffff810c2a1d>] filp_close+0x63/0x6d
> [ 86.602353] [<ffffffff810c2acf>] sys_close+0xa8/0xe2
> [ 86.607429] [<ffffffff81008602>] system_call_fastpath+0x16/0x1b
> [ 86.613516] Rebooting in 1 seconds..Press any key to enter the menu
Hi Ingo
Seems to be commit c23f3445e68e1
(vhost: replace vhost_workqueue with per-vhost kthread)
following patch should cure it ?
Thanks
[PATCH] vhost: stop worker only if created
Its illegal to call kthread_stop(NULL)
Reported-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Eric Dumazet <eric.dumazet@xxxxxxxxx>
---
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index e05557d..0a00121 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -323,7 +323,8 @@ void vhost_dev_cleanup(struct vhost_dev *dev)
dev->mm = NULL;
WARN_ON(!list_empty(&dev->work_list));
- kthread_stop(dev->worker);
+ if (dev->worker)
+ kthread_stop(dev->worker);
}
static int log_access_ok(void __user *log_base, u64 addr, unsigned long sz)
--
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