* WARNING in kernfs_get
@ 2018-09-10 7:31 syzbot
2018-10-31 9:56 ` Tetsuo Handa
2019-11-20 8:17 ` syzbot
0 siblings, 2 replies; 6+ messages in thread
From: syzbot @ 2018-09-10 7:31 UTC (permalink / raw)
To: gregkh, linux-kernel, syzkaller-bugs, tj
Hello,
syzbot found the following crash on:
HEAD commit: 9a5682765a2e Merge branch 'x86-urgent-for-linus' of git://..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1624858e400000
kernel config: https://syzkaller.appspot.com/x/.config?x=8f59875069d721b6
dashboard link: https://syzkaller.appspot.com/bug?extid=3dcb532381f98c86aeb1
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12657f0a400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=117728ae400000
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+3dcb532381f98c86aeb1@syzkaller.appspotmail.com
WARNING: CPU: 0 PID: 5659 at fs/kernfs/dir.c:494
kernfs_get.part.8+0x131/0x160 fs/kernfs/dir.c:494
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 5659 Comm: syz-executor154 Not tainted 4.19.0-rc2+ #9
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+0x1c4/0x2b4 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+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:993
RIP: 0010:kernfs_get.part.8+0x131/0x160 fs/kernfs/dir.c:494
Code: 44 05 00 00 00 00 00 48 8b 45 d0 65 48 33 04 25 28 00 00 00 75 2f 48
83 c4 60 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 df 1c 87 ff <0f> 0b eb b1 4c
89 e7 e8 d3 83 ca ff eb 81 48 89 df e8 29 83 ca ff
RSP: 0018:ffff8801d892f500 EFLAGS: 00010293
RAX: ffff8801c5f56640 RBX: ffff8801c541b8c0 RCX: ffffffff81f7b391
kobject: 'bluetooth' (00000000076788a3): kobject_add_internal:
parent: 'virtual', set: '(null)'
RDX: 0000000000000000 RSI: ffffffff81f7b3e1 RDI: 0000000000000005
RBP: ffff8801d892f588 R08: ffff8801c5f56640 R09: ffffed0038a83718
R10: ffffed0038a83718 R11: ffff8801c541b8c3 R12: 1ffff1003b125ea4
R13: 1ffff1003b125ea0 R14: 0000000000000000 R15: ffff8801d892f560
kernfs_get fs/kernfs/dir.c:493 [inline]
kernfs_new_node+0xb4/0x120 fs/kernfs/dir.c:698
kernfs_create_dir_ns+0x4d/0x160 fs/kernfs/dir.c:1021
sysfs_create_dir_ns+0x19b/0x340 fs/sysfs/dir.c:58
kobject: 'hci1' (000000003c3c3740): kobject_add_internal:
parent: 'bluetooth', set: 'devices'
create_dir lib/kobject.c:88 [inline]
kobject_add_internal+0x440/0xb60 lib/kobject.c:247
kobject: 'hci3' (00000000e8906dbf): kobject_add_internal:
parent: 'bluetooth', set: 'devices'
kobject: 'hci3' (00000000e8906dbf): kobject_uevent_env
kobject_add_varg lib/kobject.c:382 [inline]
kobject_add+0x13f/0x1b0 lib/kobject.c:426
device_add+0x3e2/0x17f0 drivers/base/core.c:1879
kobject: 'hci2' (000000009e3c3103): kobject_add_internal:
parent: 'bluetooth', set: 'devices'
hci_register_dev+0x3e6/0xb80 net/bluetooth/hci_core.c:3196
kobject: 'hci2' (000000009e3c3103): kobject_uevent_env
__vhci_create_device+0x2c1/0x580 drivers/bluetooth/hci_vhci.c:139
vhci_create_device drivers/bluetooth/hci_vhci.c:163 [inline]
vhci_get_user drivers/bluetooth/hci_vhci.c:219 [inline]
vhci_write+0x2de/0x470 drivers/bluetooth/hci_vhci.c:299
call_write_iter include/linux/fs.h:1807 [inline]
new_sync_write fs/read_write.c:474 [inline]
__vfs_write+0x6b8/0x9f0 fs/read_write.c:487
kobject: 'hci3' (00000000e8906dbf): fill_kobj_path: path
= '/devices/virtual/bluetooth/hci3'
kobject: 'hci1' (000000003c3c3740): kobject_uevent_env
vfs_write+0x1fc/0x560 fs/read_write.c:549
ksys_write+0x101/0x260 fs/read_write.c:598
kobject: 'hci1' (000000003c3c3740): fill_kobj_path: path
= '/devices/virtual/bluetooth/hci1'
__do_sys_write fs/read_write.c:610 [inline]
__se_sys_write fs/read_write.c:607 [inline]
__x64_sys_write+0x73/0xb0 fs/read_write.c:607
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
kobject: 'hci6': free name
kobject: 'rfkill160' (000000007e905e9b): kobject_add_internal:
parent: 'hci3', set: 'devices'
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x440e49
Code: e8 ac e8 ff ff 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 0b 0a fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffce43766e8 EFLAGS: 00000213 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000440e49
RDX: 0000000000000002 RSI: 00000000200000c0 RDI: 0000000000000003
kobject: 'hci2' (000000009e3c3103): fill_kobj_path: path
= '/devices/virtual/bluetooth/hci2'
RBP: 0000000000000000 R08: 00000000004002c8 R09: 00000000004002c8
R10: 000000000075f880 R11: 0000000000000213 R12: 000000000000c1e3
R13: 0000000000401d70 R14: 0000000000000000 R15: 0000000000000000
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] 6+ messages in thread* Re: WARNING in kernfs_get
2018-09-10 7:31 WARNING in kernfs_get syzbot
@ 2018-10-31 9:56 ` Tetsuo Handa
2019-11-20 8:17 ` syzbot
1 sibling, 0 replies; 6+ messages in thread
From: Tetsuo Handa @ 2018-10-31 9:56 UTC (permalink / raw)
To: gregkh, tj; +Cc: syzbot, linux-kernel, syzkaller-bugs
On 2018/09/10 16:31, syzbot wrote:
> HEAD commit: 9a5682765a2e Merge branch 'x86-urgent-for-linus' of git://..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=1624858e400000
> kernel config: https://syzkaller.appspot.com/x/.config?x=8f59875069d721b6
> dashboard link: https://syzkaller.appspot.com/bug?extid=3dcb532381f98c86aeb1
> compiler: gcc (GCC) 8.0.1 20180413 (experimental)
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12657f0a400000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=117728ae400000
Here is a simplified reproducer.
----------
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
int main(int argc, char *argv[])
{
int i;
for (i = 0; i < 16; i++)
if (fork() == 0)
while (1) {
int fd = open("/dev/vhci", O_WRONLY);
write(fd, "\xff\x80", 2);
close(fd);
}
while (1)
pause();
return 0;
}
----------
According to debug printk() patch,
atomic_read(&kn->active) == KN_DEACTIVATED_BIAS when we hit
WARN_ON(!atomic_read(&kn->count)) at kernfs_get().
Therefore, I guess that the caller is failing to check whether
kn is already deactivated (and hence need to recreate a new
entry by that name) before reusing existing kn.
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: WARNING in kernfs_get
2018-09-10 7:31 WARNING in kernfs_get syzbot
2018-10-31 9:56 ` Tetsuo Handa
@ 2019-11-20 8:17 ` syzbot
2019-11-20 8:29 ` Greg KH
1 sibling, 1 reply; 6+ messages in thread
From: syzbot @ 2019-11-20 8:17 UTC (permalink / raw)
To: benh, gregkh, linux-kernel, penguin-kernel, rafael,
syzkaller-bugs, tj, torvalds
syzbot has bisected this bug to:
commit 726e41097920a73e4c7c33385dcc0debb1281e18
Author: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date: Tue Jul 10 00:29:10 2018 +0000
drivers: core: Remove glue dirs from sysfs earlier
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=17a101cee00000
start commit: 9a568276 Merge branch 'x86-urgent-for-linus' of git://git...
git tree: upstream
final crash: https://syzkaller.appspot.com/x/report.txt?x=146101cee00000
console output: https://syzkaller.appspot.com/x/log.txt?x=106101cee00000
kernel config: https://syzkaller.appspot.com/x/.config?x=8f59875069d721b6
dashboard link: https://syzkaller.appspot.com/bug?extid=3dcb532381f98c86aeb1
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12657f0a400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=117728ae400000
Reported-by: syzbot+3dcb532381f98c86aeb1@syzkaller.appspotmail.com
Fixes: 726e41097920 ("drivers: core: Remove glue dirs from sysfs earlier")
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: WARNING in kernfs_get
2019-11-20 8:17 ` syzbot
@ 2019-11-20 8:29 ` Greg KH
2019-11-20 8:53 ` Dmitry Vyukov
2019-11-20 10:42 ` Tetsuo Handa
0 siblings, 2 replies; 6+ messages in thread
From: Greg KH @ 2019-11-20 8:29 UTC (permalink / raw)
To: syzbot
Cc: Benjamin Herrenschmidt, linux-kernel, penguin-kernel, rafael,
syzkaller-bugs, tj, torvalds
On Wed, Nov 20, 2019 at 12:17:01AM -0800, syzbot wrote:
> syzbot has bisected this bug to:
>
> commit 726e41097920a73e4c7c33385dcc0debb1281e18
> Author: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Date: Tue Jul 10 00:29:10 2018 +0000
>
> drivers: core: Remove glue dirs from sysfs earlier
>
> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=17a101cee00000
> start commit: 9a568276 Merge branch 'x86-urgent-for-linus' of git://git...
> git tree: upstream
> final crash: https://syzkaller.appspot.com/x/report.txt?x=146101cee00000
> console output: https://syzkaller.appspot.com/x/log.txt?x=106101cee00000
> kernel config: https://syzkaller.appspot.com/x/.config?x=8f59875069d721b6
> dashboard link: https://syzkaller.appspot.com/bug?extid=3dcb532381f98c86aeb1
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12657f0a400000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=117728ae400000
>
> Reported-by: syzbot+3dcb532381f98c86aeb1@syzkaller.appspotmail.com
> Fixes: 726e41097920 ("drivers: core: Remove glue dirs from sysfs earlier")
>
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection
Again, I think this should be resolved with ac43432cb1f5 ("driver core:
Fix use-after-free and double free on glue directory")
Is there any way to run the reproducer on a newer tree?
thanks,
greg k-h
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: WARNING in kernfs_get
2019-11-20 8:29 ` Greg KH
@ 2019-11-20 8:53 ` Dmitry Vyukov
2019-11-20 10:42 ` Tetsuo Handa
1 sibling, 0 replies; 6+ messages in thread
From: Dmitry Vyukov @ 2019-11-20 8:53 UTC (permalink / raw)
To: Greg KH
Cc: syzbot, Benjamin Herrenschmidt, LKML, Tetsuo Handa, rafael,
syzkaller-bugs, Tejun Heo, Linus Torvalds
On Wed, Nov 20, 2019 at 9:30 AM Greg KH <gregkh@linuxfoundation.org> wrote:
>
> On Wed, Nov 20, 2019 at 12:17:01AM -0800, syzbot wrote:
> > syzbot has bisected this bug to:
> >
> > commit 726e41097920a73e4c7c33385dcc0debb1281e18
> > Author: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> > Date: Tue Jul 10 00:29:10 2018 +0000
> >
> > drivers: core: Remove glue dirs from sysfs earlier
> >
> > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=17a101cee00000
> > start commit: 9a568276 Merge branch 'x86-urgent-for-linus' of git://git...
> > git tree: upstream
> > final crash: https://syzkaller.appspot.com/x/report.txt?x=146101cee00000
> > console output: https://syzkaller.appspot.com/x/log.txt?x=106101cee00000
> > kernel config: https://syzkaller.appspot.com/x/.config?x=8f59875069d721b6
> > dashboard link: https://syzkaller.appspot.com/bug?extid=3dcb532381f98c86aeb1
> > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12657f0a400000
> > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=117728ae400000
> >
> > Reported-by: syzbot+3dcb532381f98c86aeb1@syzkaller.appspotmail.com
> > Fixes: 726e41097920 ("drivers: core: Remove glue dirs from sysfs earlier")
> >
> > For information about bisection process see: https://goo.gl/tpsmEJ#bisection
>
> Again, I think this should be resolved with ac43432cb1f5 ("driver core:
> Fix use-after-free and double free on glue directory")
>
> Is there any way to run the reproducer on a newer tree?
The generic fix testing instruction should work:
https://github.com/google/syzkaller/blob/master/docs/syzbot.md#testing-patches
Note: you don't need to attach any patch, just pointing to a
tree/branch works too.
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: WARNING in kernfs_get
2019-11-20 8:29 ` Greg KH
2019-11-20 8:53 ` Dmitry Vyukov
@ 2019-11-20 10:42 ` Tetsuo Handa
1 sibling, 0 replies; 6+ messages in thread
From: Tetsuo Handa @ 2019-11-20 10:42 UTC (permalink / raw)
To: Greg KH, syzbot
Cc: Benjamin Herrenschmidt, linux-kernel, rafael, syzkaller-bugs, tj,
torvalds
On 2019/11/20 17:29, Greg KH wrote:
> Again, I think this should be resolved with ac43432cb1f5 ("driver core:
> Fix use-after-free and double free on glue directory")
Last occurrence was v5.3-rc3 and that patch went to v5.3-rc4. Should be fixed.
#syz fix: driver core: Fix use-after-free and double free on glue directory
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2019-11-20 10:43 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2018-09-10 7:31 WARNING in kernfs_get syzbot
2018-10-31 9:56 ` Tetsuo Handa
2019-11-20 8:17 ` syzbot
2019-11-20 8:29 ` Greg KH
2019-11-20 8:53 ` Dmitry Vyukov
2019-11-20 10:42 ` Tetsuo Handa
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