* WARNING in close_fs_devices
@ 2018-06-05 13:17 syzbot
2018-06-06 16:01 ` [PATCH] btrfs: fix race between free_stale_devices and close_fs_devices Anand Jain
` (2 more replies)
0 siblings, 3 replies; 8+ messages in thread
From: syzbot @ 2018-06-05 13:17 UTC (permalink / raw)
To: clm, dsterba, jbacik, linux-btrfs, linux-kernel, syzkaller-bugs
Hello,
syzbot found the following crash on:
HEAD commit: 716a685fdb89 Merge branch 'x86-hyperv-for-linus' of git://..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15c5f46f800000
kernel config: https://syzkaller.appspot.com/x/.config?x=4f65cd4286737868
dashboard link: https://syzkaller.appspot.com/bug?extid=ceb2606025ec1cc3479c
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=1251799f800000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=177f3edf800000
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+ceb2606025ec1cc3479c@syzkaller.appspotmail.com
WARNING: CPU: 1 PID: 4499 at fs/btrfs/volumes.c:1071
close_fs_devices+0xbc7/0xfa0 fs/btrfs/volumes.c:1071
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 4499 Comm: syz-executor921 Not tainted 4.17.0+ #84
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1b9/0x294 lib/dump_stack.c:113
panic+0x22f/0x4de kernel/panic.c:184
__warn.cold.8+0x163/0x1b3 kernel/panic.c:536
report_bug+0x252/0x2d0 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:178 [inline]
do_error_trap+0x1fc/0x4d0 arch/x86/kernel/traps.c:296
do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316
invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:992
RIP: 0010:close_fs_devices+0xbc7/0xfa0 fs/btrfs/volumes.c:1071
Code: a0 b4 fe 0f 0b e8 89 a0 b4 fe 0f 0b 48 89 f7 e8 8f 10 f1 fe e9 f6 f5
ff ff e8 75 a0 b4 fe 0f 0b e9 fd fd ff ff e8 69 a0 b4 fe <0f> 0b e9 a8 fd
ff ff 48 8b bd 58 fd ff ff e8 26 11 f1 fe e9 35 fd
RSP: 0018:ffff8801ad45e530 EFLAGS: 00010293
RAX: ffff8801adb96200 RBX: 0000000000000001 RCX: ffffffff82c4ae3d
RDX: 0000000000000000 RSI: ffffffff82c4b097 RDI: 0000000000000007
RBP: ffff8801ad45e830 R08: ffff8801adb96200 R09: 0000000000000006
R10: ffff8801adb96200 R11: 0000000000000000 R12: ffffed0035a8bcc1
R13: 1ffff10035a8bcf9 R14: ffff8801ad45e7c8 R15: ffff8801b4431688
btrfs_close_devices+0x29/0x150 fs/btrfs/volumes.c:1085
open_ctree+0x589/0x7898 fs/btrfs/disk-io.c:3358
btrfs_fill_super fs/btrfs/super.c:1202 [inline]
btrfs_mount_root+0x16df/0x1e70 fs/btrfs/super.c:1593
mount_fs+0xae/0x328 fs/super.c:1277
vfs_kern_mount.part.34+0xd4/0x4d0 fs/namespace.c:1037
vfs_kern_mount+0x40/0x60 fs/namespace.c:1027
btrfs_mount+0x4a1/0x213e fs/btrfs/super.c:1661
mount_fs+0xae/0x328 fs/super.c:1277
vfs_kern_mount.part.34+0xd4/0x4d0 fs/namespace.c:1037
vfs_kern_mount fs/namespace.c:1027 [inline]
do_new_mount fs/namespace.c:2518 [inline]
do_mount+0x564/0x30b0 fs/namespace.c:2848
ksys_mount+0x12d/0x140 fs/namespace.c:3064
__do_sys_mount fs/namespace.c:3078 [inline]
__se_sys_mount fs/namespace.c:3075 [inline]
__x64_sys_mount+0xbe/0x150 fs/namespace.c:3075
do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4431da
Code: b8 08 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 fd e5 fb ff c3 66 2e 0f
1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff
ff 0f 83 da e5 fb ff c3 66 0f 1f 84 00 00 00 00 00
RSP: 002b:00007ffe426bfd28 EFLAGS: 00000286 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004431da
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007ffe426bfd40
RBP: 0000000000000004 R08: 00000000200006c0 R09: 000000000000000a
R10: 0000000000000001 R11: 0000000000000286 R12: 0000000000000010
R13: 0000000008100000 R14: 0031656c69662f2e R15: fe03f80fe03f80ff
Dumping ftrace buffer:
(ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..
---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.
syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with
syzbot.
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches
^ permalink raw reply [flat|nested] 8+ messages in thread* [PATCH] btrfs: fix race between free_stale_devices and close_fs_devices
2018-06-05 13:17 WARNING in close_fs_devices syzbot
@ 2018-06-06 16:01 ` Anand Jain
2018-06-07 16:12 ` David Sterba
2018-06-19 17:15 ` WARNING in close_fs_devices David Sterba
2018-06-19 17:17 ` David Sterba
2 siblings, 1 reply; 8+ messages in thread
From: Anand Jain @ 2018-06-06 16:01 UTC (permalink / raw)
To: linux-btrfs
%fs_devices can be free-ed by btrfs_free_stale_devices() when the
close_fs_devices() drops fs_devices::opened to zero, but close_fs_devices
tries to access the %fs_devices again without the device_list_mutex.
Fix this by bringing the %fs_devices access with in the device_list_mutex.
Stack trace as below.
HEAD commit: 716a685fdb89 Merge branch 'x86-hyperv-for-linus' of git://..
::
CPU: 1 PID: 4499 Comm: syz-executor921 Not tainted 4.17.0+ #84
::
WARNING: CPU: 1 PID: 4499 at fs/btrfs/volumes.c:1071 close_fs_devices+0xbc7/0xfa0 fs/btrfs/volumes.c:1071
Kernel panic - not syncing: panic_on_warn set ...
::
RIP: 0010:close_fs_devices+0xbc7/0xfa0 fs/btrfs/volumes.c:1071
::
btrfs_close_devices+0x29/0x150 fs/btrfs/volumes.c:1085
open_ctree+0x589/0x7898 fs/btrfs/disk-io.c:3358
btrfs_fill_super fs/btrfs/super.c:1202 [inline]
btrfs_mount_root+0x16df/0x1e70 fs/btrfs/super.c:1593
mount_fs+0xae/0x328 fs/super.c:1277
vfs_kern_mount.part.34+0xd4/0x4d0 fs/namespace.c:1037
vfs_kern_mount+0x40/0x60 fs/namespace.c:1027
btrfs_mount+0x4a1/0x213e fs/btrfs/super.c:1661
mount_fs+0xae/0x328 fs/super.c:1277
Reported-by: syzbot+ceb2606025ec1cc3479c@syzkaller.appspotmail.com
Signed-off-by: Anand Jain <anand.jain@oracle.com>
---
fs/btrfs/volumes.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index c2b7d66192e8..32fba4e24027 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1153,6 +1153,12 @@ static int close_fs_devices(struct btrfs_fs_devices *fs_devices)
btrfs_prepare_close_one_device(device);
list_add(&device->dev_list, &pending_put);
}
+
+ WARN_ON(fs_devices->open_devices);
+ WARN_ON(fs_devices->rw_devices);
+ fs_devices->opened = 0;
+ clear_bit(BTRFS_VOLUME_STATE_SEEDING, &fs_devices->volume_state);
+
mutex_unlock(&fs_devices->device_list_mutex);
/*
@@ -1169,11 +1175,6 @@ static int close_fs_devices(struct btrfs_fs_devices *fs_devices)
call_rcu(&device->rcu, free_device_rcu);
}
- WARN_ON(fs_devices->open_devices);
- WARN_ON(fs_devices->rw_devices);
- fs_devices->opened = 0;
- clear_bit(BTRFS_VOLUME_STATE_SEEDING, &fs_devices->volume_state);
-
return 0;
}
--
2.15.0
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH] btrfs: fix race between free_stale_devices and close_fs_devices
2018-06-06 16:01 ` [PATCH] btrfs: fix race between free_stale_devices and close_fs_devices Anand Jain
@ 2018-06-07 16:12 ` David Sterba
0 siblings, 0 replies; 8+ messages in thread
From: David Sterba @ 2018-06-07 16:12 UTC (permalink / raw)
To: Anand Jain; +Cc: linux-btrfs
On Thu, Jun 07, 2018 at 12:01:09AM +0800, Anand Jain wrote:
> %fs_devices can be free-ed by btrfs_free_stale_devices() when the
> close_fs_devices() drops fs_devices::opened to zero, but close_fs_devices
> tries to access the %fs_devices again without the device_list_mutex.
>
> Fix this by bringing the %fs_devices access with in the device_list_mutex.
>
> Stack trace as below.
>
> HEAD commit: 716a685fdb89 Merge branch 'x86-hyperv-for-linus' of git://..
> ::
> CPU: 1 PID: 4499 Comm: syz-executor921 Not tainted 4.17.0+ #84
> ::
> WARNING: CPU: 1 PID: 4499 at fs/btrfs/volumes.c:1071 close_fs_devices+0xbc7/0xfa0 fs/btrfs/volumes.c:1071
> Kernel panic - not syncing: panic_on_warn set ...
> ::
> RIP: 0010:close_fs_devices+0xbc7/0xfa0 fs/btrfs/volumes.c:1071
> ::
> btrfs_close_devices+0x29/0x150 fs/btrfs/volumes.c:1085
> open_ctree+0x589/0x7898 fs/btrfs/disk-io.c:3358
> btrfs_fill_super fs/btrfs/super.c:1202 [inline]
> btrfs_mount_root+0x16df/0x1e70 fs/btrfs/super.c:1593
> mount_fs+0xae/0x328 fs/super.c:1277
> vfs_kern_mount.part.34+0xd4/0x4d0 fs/namespace.c:1037
> vfs_kern_mount+0x40/0x60 fs/namespace.c:1027
> btrfs_mount+0x4a1/0x213e fs/btrfs/super.c:1661
> mount_fs+0xae/0x328 fs/super.c:1277
>
> Reported-by: syzbot+ceb2606025ec1cc3479c@syzkaller.appspotmail.com
> Signed-off-by: Anand Jain <anand.jain@oracle.com>
> ---
> fs/btrfs/volumes.c | 11 ++++++-----
> 1 file changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index c2b7d66192e8..32fba4e24027 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -1153,6 +1153,12 @@ static int close_fs_devices(struct btrfs_fs_devices *fs_devices)
> btrfs_prepare_close_one_device(device);
> list_add(&device->dev_list, &pending_put);
> }
> +
> + WARN_ON(fs_devices->open_devices);
> + WARN_ON(fs_devices->rw_devices);
> + fs_devices->opened = 0;
> + clear_bit(BTRFS_VOLUME_STATE_SEEDING, &fs_devices->volume_state);
This is from some other patch.
Moving that to the protected section should fix it but we'd also need to
extend the critical section to:
1047 if (--fs_devices->opened > 0)
1048 return 0;
Otherwise I think there are still some cornercases to fix as the
fs_devices members are not accessed properly everywhere. This patch
should be enough to fix the parallel mount and stale device freeing
races though, so I'll queue it up.
> +
> mutex_unlock(&fs_devices->device_list_mutex);
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: WARNING in close_fs_devices
2018-06-05 13:17 WARNING in close_fs_devices syzbot
2018-06-06 16:01 ` [PATCH] btrfs: fix race between free_stale_devices and close_fs_devices Anand Jain
@ 2018-06-19 17:15 ` David Sterba
2018-06-19 17:18 ` syzbot
2018-06-19 17:18 ` syzbot
2018-06-19 17:17 ` David Sterba
2 siblings, 2 replies; 8+ messages in thread
From: David Sterba @ 2018-06-19 17:15 UTC (permalink / raw)
To: syzbot; +Cc: clm, dsterba, jbacik, linux-btrfs, linux-kernel, syzkaller-bugs
On Tue, Jun 05, 2018 at 06:17:03AM -0700, syzbot wrote:
> syzbot found the following crash on:
>
> HEAD commit: 716a685fdb89 Merge branch 'x86-hyperv-for-linus' of git://..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=15c5f46f800000
> kernel config: https://syzkaller.appspot.com/x/.config?x=4f65cd4286737868
> dashboard link: https://syzkaller.appspot.com/bug?extid=ceb2606025ec1cc3479c
> compiler: gcc (GCC) 8.0.1 20180413 (experimental)
> syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=1251799f800000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=177f3edf800000
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+ceb2606025ec1cc3479c@syzkaller.appspotmail.com
#syz test git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux.git test-syzbot-fs-devices
The patches are work in progress but pass fstests and should address
these syzbot reports:
https://syzkaller.appspot.com/bug?extid=ceb2606025ec1cc3479c
syzbot+ceb2606025ec1cc3479c@syzkaller.appspotmail.com
https://syzkaller.appspot.com/bug?extid=909a5177749d7990ffa4
syzbot+909a5177749d7990ffa4@syzkaller.appspotmail.com
https://syzkaller.appspot.com/bug?extid=923aa93978c7ad27a9b1
syzbot+923aa93978c7ad27a9b1@syzkaller.appspotmail.com
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: Re: WARNING in close_fs_devices
2018-06-19 17:15 ` WARNING in close_fs_devices David Sterba
@ 2018-06-19 17:18 ` syzbot
2018-06-19 17:18 ` syzbot
1 sibling, 0 replies; 8+ messages in thread
From: syzbot @ 2018-06-19 17:18 UTC (permalink / raw)
To: David Sterba
Cc: clm, dsterba, dsterba, jbacik, linux-btrfs, linux-kernel, syzkaller-bugs
> On Tue, Jun 05, 2018 at 06:17:03AM -0700, syzbot wrote:
>> syzbot found the following crash on:
>> HEAD commit: 716a685fdb89 Merge branch 'x86-hyperv-for-linus' of
>> git://..
>> git tree: upstream
>> console output: https://syzkaller.appspot.com/x/log.txt?x=15c5f46f800000
>> kernel config:
>> https://syzkaller.appspot.com/x/.config?x=4f65cd4286737868
>> dashboard link:
>> https://syzkaller.appspot.com/bug?extid=ceb2606025ec1cc3479c
>> compiler: gcc (GCC) 8.0.1 20180413 (experimental)
>> syzkaller
>> repro:https://syzkaller.appspot.com/x/repro.syz?x=1251799f800000
>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=177f3edf800000
>> IMPORTANT: if you fix the bug, please add the following tag to the
>> commit:
>> Reported-by: syzbot+ceb2606025ec1cc3479c@syzkaller.appspotmail.com
> #syz test git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux.git
> test-syzbot-fs-devices
unknown command "test"
> The patches are work in progress but pass fstests and should address
> these syzbot reports:
> https://syzkaller.appspot.com/bug?extid=ceb2606025ec1cc3479c
> syzbot+ceb2606025ec1cc3479c@syzkaller.appspotmail.com
> https://syzkaller.appspot.com/bug?extid=909a5177749d7990ffa4
> syzbot+909a5177749d7990ffa4@syzkaller.appspotmail.com
> https://syzkaller.appspot.com/bug?extid=923aa93978c7ad27a9b1
> syzbot+923aa93978c7ad27a9b1@syzkaller.appspotmail.com
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: Re: WARNING in close_fs_devices
2018-06-19 17:15 ` WARNING in close_fs_devices David Sterba
2018-06-19 17:18 ` syzbot
@ 2018-06-19 17:18 ` syzbot
1 sibling, 0 replies; 8+ messages in thread
From: syzbot @ 2018-06-19 17:18 UTC (permalink / raw)
To: David Sterba
Cc: clm, dsterba, dsterba, jbacik, linux-btrfs, linux-kernel, syzkaller-bugs
> On Tue, Jun 05, 2018 at 06:17:03AM -0700, syzbot wrote:
>> syzbot found the following crash on:
>> HEAD commit: 716a685fdb89 Merge branch 'x86-hyperv-for-linus' of
>> git://..
>> git tree: upstream
>> console output: https://syzkaller.appspot.com/x/log.txt?x=15c5f46f800000
>> kernel config:
>> https://syzkaller.appspot.com/x/.config?x=4f65cd4286737868
>> dashboard link:
>> https://syzkaller.appspot.com/bug?extid=ceb2606025ec1cc3479c
>> compiler: gcc (GCC) 8.0.1 20180413 (experimental)
>> syzkaller
>> repro:https://syzkaller.appspot.com/x/repro.syz?x=1251799f800000
>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=177f3edf800000
>> IMPORTANT: if you fix the bug, please add the following tag to the
>> commit:
>> Reported-by: syzbot+ceb2606025ec1cc3479c@syzkaller.appspotmail.com
> #syz test git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux.git
> test-syzbot-fs-devices
unknown command "test"
> The patches are work in progress but pass fstests and should address
> these syzbot reports:
> https://syzkaller.appspot.com/bug?extid=ceb2606025ec1cc3479c
> syzbot+ceb2606025ec1cc3479c@syzkaller.appspotmail.com
> https://syzkaller.appspot.com/bug?extid=909a5177749d7990ffa4
> syzbot+909a5177749d7990ffa4@syzkaller.appspotmail.com
> https://syzkaller.appspot.com/bug?extid=923aa93978c7ad27a9b1
> syzbot+923aa93978c7ad27a9b1@syzkaller.appspotmail.com
> --
> You received this message because you are subscribed to the Google
> Groups "syzkaller-bugs" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to syzkaller-bugs+unsubscribe@googlegroups.com.
> To view this discussion on the web visit
> https://groups.google.com/d/msgid/syzkaller-bugs/20180619171513.GT24375%40twin.jikos.cz.
> For more options, visit https://groups.google.com/d/optout.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: WARNING in close_fs_devices
2018-06-05 13:17 WARNING in close_fs_devices syzbot
2018-06-06 16:01 ` [PATCH] btrfs: fix race between free_stale_devices and close_fs_devices Anand Jain
2018-06-19 17:15 ` WARNING in close_fs_devices David Sterba
@ 2018-06-19 17:17 ` David Sterba
2018-06-19 17:42 ` syzbot
2 siblings, 1 reply; 8+ messages in thread
From: David Sterba @ 2018-06-19 17:17 UTC (permalink / raw)
To: syzbot; +Cc: clm, dsterba, jbacik, linux-btrfs, linux-kernel, syzkaller-bugs
On Tue, Jun 05, 2018 at 06:17:03AM -0700, syzbot wrote:
> syzbot found the following crash on:
>
> HEAD commit: 716a685fdb89 Merge branch 'x86-hyperv-for-linus' of git://..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=15c5f46f800000
> kernel config: https://syzkaller.appspot.com/x/.config?x=4f65cd4286737868
> dashboard link: https://syzkaller.appspot.com/bug?extid=ceb2606025ec1cc3479c
> compiler: gcc (GCC) 8.0.1 20180413 (experimental)
> syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=1251799f800000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=177f3edf800000
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+ceb2606025ec1cc3479c@syzkaller.appspotmail.com
Again with the right syntax:
#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux.git test-syzbot-fs-devices
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2018-06-19 17:42 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-06-05 13:17 WARNING in close_fs_devices syzbot
2018-06-06 16:01 ` [PATCH] btrfs: fix race between free_stale_devices and close_fs_devices Anand Jain
2018-06-07 16:12 ` David Sterba
2018-06-19 17:15 ` WARNING in close_fs_devices David Sterba
2018-06-19 17:18 ` syzbot
2018-06-19 17:18 ` syzbot
2018-06-19 17:17 ` David Sterba
2018-06-19 17:42 ` syzbot
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