WARNING in blk_mq_sched_free_requests

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: d1fdb6d8 Linux 5.2-rc4
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=105ade6aa00000
kernel config: https://syzkaller.appspot.com/x/.config?x=fa9f7e1b6a8bb586
dashboard link: https://syzkaller.appspot.com/bug?extid=b9d0d56867048c7bcfde
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11c67dd2a00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=154be66aa00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+b9d0d5...@syzkaller.appspotmail.com

Code: e8 bc b5 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff
ff 0f 83 2b 09 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f735bcf2d88 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000006dbc38 RCX: 00000000004466e9
RDX: 0000000000000000 RSI: 0000000000004c80 RDI: 0000000000000003
RBP: 00000000006dbc30 R08: 0000000000000002 R09: 0000000000003034
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc3c
R13: 00007f735bcf2d90 R14: 0000000000000004 R15: 20c49ba5e353f7cf
WARNING: CPU: 0 PID: 9739 at block/blk-mq-sched.c:558
blk_mq_sched_free_requests+0x207/0x290 block/blk-mq-sched.c:558
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 9739 Comm: syz-executor118 Not tainted 5.2.0-rc4 #25
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+0x172/0x1f0 lib/dump_stack.c:113
panic+0x2cb/0x744 kernel/panic.c:219
__warn.cold+0x20/0x4d kernel/panic.c:576
report_bug+0x263/0x2b0 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:179 [inline]
fixup_bug arch/x86/kernel/traps.c:174 [inline]
do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:272
do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:291
invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:986
RIP: 0010:blk_mq_sched_free_requests+0x207/0x290 block/blk-mq-sched.c:558
Code: ff e8 6d bf 30 fe 31 ff 89 c3 89 c6 e8 32 ac 4a fe 85 db 0f 85 68 fe
ff ff e8 a5 aa 4a fe 0f 0b e9 5c fe ff ff e8 99 aa 4a fe <0f> 0b e9 7f fe
ff ff 48 c7 c7 b4 e5 80 89 e8 b6 48 83 fe e9 28 fe
RSP: 0018:ffff88808ab9fa60 EFLAGS: 00010293
RAX: ffff88808c9f6340 RBX: 0000000000000001 RCX: ffffffff8326000e
RDX: 0000000000000000 RSI: ffffffff83260027 RDI: ffff88809f27b020
RBP: ffff88808ab9fab0 R08: ffff88808c9f6340 R09: ffffed1015d06be0
R10: ffffed1015d06bdf R11: ffff8880ae835efb R12: 00000000fffffff4
R13: ffff88809f27b008 R14: ffff88809ec4e658 R15: ffff88809f27b008
blk_mq_init_sched+0x32c/0x770 block/blk-mq-sched.c:542
elevator_init_mq+0xcd/0x160 block/elevator.c:622
blk_mq_init_allocated_queue+0x10e2/0x15b0 block/blk-mq.c:2921
blk_mq_init_queue+0x62/0xb0 block/blk-mq.c:2705
loop_add+0x2dd/0x8d0 drivers/block/loop.c:2004
loop_control_ioctl drivers/block/loop.c:2157 [inline]
loop_control_ioctl+0x165/0x360 drivers/block/loop.c:2139
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:509 [inline]
do_vfs_ioctl+0xd5f/0x1380 fs/ioctl.c:696
ksys_ioctl+0xab/0xd0 fs/ioctl.c:713
__do_sys_ioctl fs/ioctl.c:720 [inline]
__se_sys_ioctl fs/ioctl.c:718 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4466e9
Code: e8 bc b5 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff
ff 0f 83 2b 09 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f735bcf2d88 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000006dbc38 RCX: 00000000004466e9
RDX: 0000000000000000 RSI: 0000000000004c80 RDI: 0000000000000003
RBP: 00000000006dbc30 R08: 0000000000000002 R09: 0000000000003034
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc3c
R13: 00007f735bcf2d90 R14: 0000000000000004 R15: 20c49ba5e353f7cf
Kernel Offset: disabled
Rebooting in 86400 seconds..


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[Ming Lei]

Hello,

Thanks for your report!

Patch has been posted out:

https://lore.kernel.org/linux-block/20190611093153....@redhat.com/T/#u

Thanks,
Ming