Re: [iov_iter] 2418c34937: Initiating_system_reboot

[Oliver Sang]

hi, Al Viro,

On Wed, Apr 28, 2021 at 04:32:44AM +0000, Al Viro wrote:
> On Wed, Apr 28, 2021 at 10:37:47AM +0800, kernel test robot wrote:
> > 
> > 
> > Greeting,
> > 
> > FYI, we noticed the following commit (built with gcc-9):
> > 
> > commit: 2418c34937c42a30ef4bccd923ad664a89e1fbd4 ("iov_iter: optimize iov_iter_advance() for iovec and kvec")
> > https://git.kernel.org/cgit/linux/kernel/git/viro/vfs.git untested.iov_iter
> > 
> > 
> > in testcase: boot
> > 
> > on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G
> > 
> > caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):
> 
> Could you try https://git.kernel.org/cgit/linux/kernel/git/viro/vfs.git for-lkp
> on the same test and see what (if anything) gets spewed into dmesg?

please check attached dmesg.xz for detail

[   18.549991] ------------[ cut here ]------------
[   18.550798] WARNING: CPU: 0 PID: 124 at lib/iov_iter.c:1117 iov_iter_advance.cold+0x13/0x7b
[   18.552115] Modules linked in:
[   18.552693] CPU: 0 PID: 124 Comm: kmodloader Not tainted 5.12.0-rc2-00004-g039686f7e8a0 #1
[   18.554221] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
[   18.555733] EIP: iov_iter_advance.cold+0x13/0x7b
[   18.556616] Code: 00 00 b8 90 78 2f b2 31 c9 e8 cd 9e 79 ff 58 31 c0 5a e9 cc 4b a8 ff 6a 01 31 c9 ba 01 00 00 00 b8 c8 6d 2f b2 e8 b1 9e 79 ff <0f> 0
b 6a 01 31 c9 ba 01 00 00 00 b8 b0 6d 2f b2 31 db e8 9a 9e 79
[   18.559751] EAX: 00000000 EBX: 00000000 ECX: 00000000 EDX: 00000001
[   18.560818] ESI: 00000000 EDI: ddf89ee4 EBP: ddf89eac ESP: ddf89e5c
[   18.561894] DS: 007b ES: 007b FS: 0000 GS: 00e0 SS: 0068 EFLAGS: 00010206
[   18.563020] CR0: 80050033 CR2: a7f30844 CR3: 2deee000 CR4: 000406d0
[   18.564011] Call Trace:
[   18.564483]  do_iter_read+0x138/0x1c0
[   18.565159]  vfs_readv+0x47/0x80
[   18.565771]  ? lock_acquire+0xa8/0x2e0
[   18.566463]  ? __fget_light+0x4d/0x90
[   18.567152]  do_readv+0x5f/0xe0
[   18.567723]  __ia32_sys_readv+0x12/0x20
[   18.568451]  __do_fast_syscall_32+0x74/0xb0
[   18.569223]  do_fast_syscall_32+0x28/0x60
[   18.569977]  do_SYSENTER_32+0x15/0x20
[   18.570676]  entry_SYSENTER_32+0x9f/0xf1
[   18.571419] EIP: 0xa7f44549
[   18.571962] Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5
a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
[   18.575391] EAX: ffffffda EBX: 00000004 ECX: af810710 EDX: 00000002
[   18.576611] ESI: 00000001 EDI: 00003061 EBP: af810738 ESP: af8106e4
[   18.577748] DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b EFLAGS: 00000282
[   18.578970] irq event stamp: 2455
[   18.579587] hardirqs last  enabled at (2463): [<b10bd9b5>] console_unlock+0x455/0x610
[   18.580951] hardirqs last disabled at (2470): [<b10bd9a5>] console_unlock+0x445/0x610
[   18.582269] softirqs last  enabled at (2322): [<b19d6aad>] __do_softirq+0x29d/0x434
[   18.583483] softirqs last disabled at (2313): [<b1024220>] call_on_stack+0x40/0x50
[   18.585165] ---[ end trace 6e5f78d431f11767 ]---

Attachment: dmesg.xz
Description: application/xz