WARNING in __put_task_struct (2)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: ae16eea39a86 Add linux-next specific files for 20181008
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=12e7c6a1400000
kernel config: https://syzkaller.appspot.com/x/.config?x=42525ce985d1a955
dashboard link: https://syzkaller.appspot.com/bug?extid=1ed9dfaa984c88cf0ef8
compiler: gcc (GCC) 8.0.1 20180413 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+1ed9df...@syzkaller.appspotmail.com

WARNING: CPU: 1 PID: 16271 at kernel/fork.c:718
__put_task_struct+0x3ef/0x620 kernel/fork.c:718
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 16271 Comm: syz-executor5 Not tainted 4.19.0-rc7-next-20181008+
#89
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+0x244/0x3ab lib/dump_stack.c:113
panic+0x238/0x4e7 kernel/panic.c:184
__warn.cold.8+0x163/0x1ba kernel/panic.c:536
report_bug+0x254/0x2d0 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:178 [inline]
do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271
do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:290
invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:969
RIP: 0010:__put_task_struct+0x3ef/0x620 kernel/fork.c:718
Code: 4c 89 ee e8 d3 9d 7b 00 e9 a1 fe ff ff e8 89 53 37 00 0f 0b e9 7c fd
ff ff e8 7d 53 37 00 0f 0b e9 87 fd ff ff e8 71 53 37 00 <0f> 0b e9 d0 fc
ff ff e8 65 53 37 00 49 8d 87 90 05 00 00 31 f6 48
RSP: 0018:ffff88018dbcf808 EFLAGS: 00010293
RAX: ffff880187474180 RBX: ffff88018cc7a1c0 RCX: ffffffff8147298d
RDX: 0000000000000000 RSI: ffffffff81472cbf RDI: 0000000000000005
RBP: ffff88018dbcf8e8 R08: ffff880187474180 R09: ffffed003198f43c
R10: ffffed003198f43c R11: ffff88018cc7a1e3 R12: 1ffff10031b79f04
R13: 0000000000000000 R14: ffff88018dbcf8c0 R15: ffff88018daceb40
put_task_struct include/linux/sched/task.h:96 [inline]
rdma_restrack_del+0x2e0/0x3b0 drivers/infiniband/core/restrack.c:243
rdma_destroy_id+0x126/0xcc0 drivers/infiniband/core/cma.c:1820
ucma_close+0x114/0x310 drivers/infiniband/core/ucma.c:1767
__fput+0x3bc/0xa70 fs/file_table.c:279
____fput+0x15/0x20 fs/file_table.c:312
task_work_run+0x1e8/0x2a0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166
prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x411051
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 34 19 00 00 c3 48
83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48
89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007ffd6e8617b0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000411051
RDX: 0000000000000000 RSI: 0000000000731850 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 00007ffd6e8616e0 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000001 R14: 0000000000000156 R15: 0000000000000005
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
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[Dmitry Vyukov]

On Mon, Oct 8, 2018 at 6:12 PM, syzbot
<syzbot+1ed9df...@syzkaller.appspotmail.com> wrote:
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit: ae16eea39a86 Add linux-next specific files for 20181008
> git tree: linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=12e7c6a1400000
> kernel config: https://syzkaller.appspot.com/x/.config?x=42525ce985d1a955
> dashboard link: https://syzkaller.appspot.com/bug?extid=1ed9dfaa984c88cf0ef8
> compiler: gcc (GCC) 8.0.1 20180413 (experimental)
>
> Unfortunately, I don't have any reproducer for this crash yet.
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+1ed9df...@syzkaller.appspotmail.com

This was triggered by the following program, all is rdma-related, so
+rdma maintainers.

10:27:26 executing program 5:
r0 = openat$rdma_cm(0xffffffffffffff9c,
&(0x7f0000000380)='/dev/infiniband/rdma_cm\x00', 0x2, 0x0)
write$RDMA_USER_CM_CMD_CREATE_ID(r0, &(0x7f0000000080)={0x0, 0x18,
0xfa00, {0x0, &(0x7f0000000040)={<r1=>0xffffffffffffffff}, 0x13f}},
0x12d)
write$RDMA_USER_CM_CMD_RESOLVE_IP(r0, &(0x7f0000000200)={0x3, 0x40,
0xfa00, {{0xa, 0x4e21}, {0xa, 0x0, 0x0, @mcast1}, r1}}, 0x48)
write$RDMA_USER_CM_CMD_CREATE_ID(r0, &(0x7f0000000340)={0x0, 0x18,
0xfa00, {0x0, &(0x7f0000000300)={<r2=>0xffffffffffffffff}, 0x13f}},
0x20)
write$RDMA_USER_CM_CMD_SET_OPTION(r0, &(0x7f00000002c0)={0xe, 0x18,
0xfa00, @id_afonly={&(0x7f0000000000)=0x1, r1, 0x0, 0x2, 0x4}}, 0x20)
write$RDMA_USER_CM_CMD_RESOLVE_IP(r0, &(0x7f0000000100)={0x3, 0x40,
0xfa00, {{0x2, 0x4e21}, {0xa, 0x0, 0x0, @local}, r2}}, 0x1ff)
write$RDMA_USER_CM_CMD_DESTROY_ID(r0, &(0x7f0000000180)={0x1, 0x10,
0xfa00, {&(0x7f00000000c0), r2}}, 0x18)

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[Jason Gunthorpe]

This might be fixed in Linux-next now by this commit:

Author: Leon Romanovsky <leo...@mellanox.com>
Date: Tue Oct 2 11:48:03 2018 +0300

RDMA/restrack: Release task struct which was hold by CM_ID object


Jason

[Leon Romanovsky]

Jason,

I afraid that the opposite it more accurate.

This issue was introduced by that commit and According to linux-next
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next-history.git/tag/?h=next-20181008
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next-history.git/commit/?h=next-20181008&id=ae16eea39a86735f4ed0b5a6e9fe43c6cedb13b3
The RDMA tree has commit ed7a01fd3fd77f40b4ef2562b966a5decd8928d2,
which is exactly the one you cited above.
https://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma.git/commit/?h=for-next&id=ed7a01fd3fd77f40b4ef2562b966a5decd8928d2

Any ideas how?

Thanks

>
>
> Jason

[Dmitry Vyukov]

I marked another bug as dup of this because it looks like the same root cause:
https://syzkaller.appspot.com/bug?id=e1854417677586ce3d00f498f19816cb4fd15676
And that dup bug has a C reproducer.

[syzbot]

syzbot has found a reproducer for the following crash on:

HEAD commit: 774ea0551a29 Add linux-next specific files for 20181012
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=17f71735400000
kernel config: https://syzkaller.appspot.com/x/.config?x=273e86a7f336b114

dashboard link: https://syzkaller.appspot.com/bug?extid=1ed9dfaa984c88cf0ef8
compiler: gcc (GCC) 8.0.1 20180413 (experimental)

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1735d391400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1296a3a1400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+1ed9df...@syzkaller.appspotmail.com

audit: type=1800 audit(1539536806.030:30): pid=5454 uid=0 auid=4294967295
ses=4294967295 subj==unconfined op=collect_data cause=failed(directio)
comm="startpar" name="rmnologin" dev="sda1" ino=2423 res=0
IPVS: ftp: loaded support on port[0] = 21
WARNING: CPU: 1 PID: 5614 at kernel/fork.c:718

__put_task_struct+0x3ef/0x620 kernel/fork.c:718
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 5614 Comm: syz-executor338 Not tainted
4.19.0-rc7-next-20181012+ #93

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+0x244/0x3ab lib/dump_stack.c:113
panic+0x238/0x4e7 kernel/panic.c:184
__warn.cold.8+0x163/0x1ba kernel/panic.c:536
report_bug+0x254/0x2d0 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:178 [inline]
do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271
do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:290
invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:969
RIP: 0010:__put_task_struct+0x3ef/0x620 kernel/fork.c:718

Code: 4c 89 ee e8 c3 a3 7b 00 e9 a1 fe ff ff e8 69 55 37 00 0f 0b e9 7c fd
ff ff e8 5d 55 37 00 0f 0b e9 87 fd ff ff e8 51 55 37 00 <0f> 0b e9 d0 fc
ff ff e8 45 55 37 00 49 8d 87 90 05 00 00 31 f6 48
RSP: 0018:ffff8801d7fcee48 EFLAGS: 00010293
RAX: ffff8801d7ffe5c0 RBX: ffff8801d82be540 RCX: ffffffff814711cd
RDX: 0000000000000000 RSI: ffffffff814714ff RDI: 0000000000000005
RBP: ffff8801d7fcef28 R08: ffff8801d7ffe5c0 R09: ffffed003b057cac
R10: ffffed003b057cac R11: ffff8801d82be563 R12: 1ffff1003aff9dcc
R13: 0000000000000000 R14: ffff8801d7fcef00 R15: ffff8801d7f7a9c0

put_task_struct include/linux/sched/task.h:96 [inline]
rdma_restrack_del+0x2e0/0x3b0 drivers/infiniband/core/restrack.c:243
rdma_destroy_id+0x126/0xcc0 drivers/infiniband/core/cma.c:1820
ucma_close+0x114/0x310 drivers/infiniband/core/ucma.c:1767
__fput+0x3bc/0xa70 fs/file_table.c:279
____fput+0x15/0x20 fs/file_table.c:312
task_work_run+0x1e8/0x2a0 kernel/task_work.c:113

exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0x1ad2/0x2610 kernel/exit.c:867
do_group_exit+0x177/0x440 kernel/exit.c:970
get_signal+0x8a8/0x1970 kernel/signal.c:2517
do_signal+0x9c/0x21c0 arch/x86/kernel/signal.c:816
exit_to_usermode_loop+0x2e5/0x380 arch/x86/entry/common.c:162

prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe

RIP: 0033:0x4460a9
Code: Bad RIP value.
RSP: 002b:00007f0e9c1a9da8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00000000006dbc48 RCX: 00000000004460a9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00000000006dbc48
RBP: 00000000006dbc40 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc4c
R13: 666e692f7665642f R14: 0100000000000000 R15: 0000000000000003