syzbot


WARNING in reconnect_path
Status: fixed on 2020/02/16 09:59
Reported-by: syzbot+465415c9633d5fbe6f01@syzkaller.appspotmail.com
Fix commit: b6e209a13a61 exportfs: fix 'passing zero to ERR_PTR()' warning
First crash: 920d, last: 859d

Cause bisection: introduced by (bisect log) :
commit e41d58185f1444368873d4d7422f7664a68be61d
Author: Dmitry Vyukov <dvyukov@google.com>
Date: Wed Jul 12 21:34:35 2017 +0000

  fault-inject: support systematic fault injection

Crash: WARNING in reconnect_path (log)
Repro: C syz .config

Fix bisection: fixed by (bisect log) :
commit b6e209a13a61b65848e214319e3348e5e23346cb
Author: YueHaibing <yuehaibing@huawei.com>
Date: Mon Nov 19 03:32:41 2018 +0000

  exportfs: fix 'passing zero to ERR_PTR()' warning

similar bugs (3):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 WARNING in reconnect_path 1 1069d 1069d 0/1 auto-closed as invalid on 2019/10/25 08:44
linux-4.19 WARNING in reconnect_path (2) 1 919d 919d 0/1 auto-closed as invalid on 2020/03/17 01:24
upstream WARNING in reconnect_path 6 1405d 1496d 0/22 auto-closed as invalid on 2019/02/22 10:34

Sample crash report:
RDX: 0000000000400000 RSI: 0000000020000000 RDI: 00000000ffffff9c
RBP: 0000000000000000 R08: 0000000000000002 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000009e82
R13: 0000000000000005 R14: 00007ffd6bd2df50 R15: 0000000000000000
------------[ cut here ]------------
WARNING: CPU: 0 PID: 6865 at fs/exportfs/expfs.c:96 clear_disconnected fs/exportfs/expfs.c:96 [inline]
WARNING: CPU: 0 PID: 6865 at fs/exportfs/expfs.c:96 reconnect_path+0x4a6/0x630 fs/exportfs/expfs.c:232
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 6865 Comm: syz-executor304 Not tainted 4.14.154 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x142/0x197 lib/dump_stack.c:58
 panic+0x1f9/0x42d kernel/panic.c:183
 __warn.cold+0x2f/0x2f kernel/panic.c:547
 report_bug+0x216/0x254 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:177 [inline]
 fixup_bug arch/x86/kernel/traps.c:172 [inline]
 do_error_trap+0x1bb/0x310 arch/x86/kernel/traps.c:295
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:314
 invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:963
RIP: 0010:clear_disconnected fs/exportfs/expfs.c:96 [inline]
RIP: 0010:reconnect_path+0x4a6/0x630 fs/exportfs/expfs.c:232
RSP: 0018:ffff888092807bf0 EFLAGS: 00010297
RAX: ffff8880935a41c0 RBX: dffffc0000000000 RCX: 1ffff110126b4946
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff8880941b3e00
RBP: ffff888092807c40 R08: ffff8880935a41c0 R09: 0000000000000000
R10: 0000000000000000 R11: ffff8880935a41c0 R12: ffff8880941b3dc0
R13: dffffc0000000000 R14: ffff8880941b3dc0 R15: ffff8880991e1820
 exportfs_decode_fh+0x3cc/0x5e2 fs/exportfs/expfs.c:448
 do_handle_to_path fs/fhandle.c:153 [inline]
 handle_to_path fs/fhandle.c:208 [inline]
 do_handle_open+0x285/0x640 fs/fhandle.c:224
 SYSC_open_by_handle_at fs/fhandle.c:266 [inline]
 SyS_open_by_handle_at+0x27/0x30 fs/fhandle.c:257
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x441b29
RSP: 002b:00007ffd6bd2def8 EFLAGS: 00000246 ORIG_RAX: 0000000000000130
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000441b29
RDX: 0000000000400000 RSI: 0000000020000000 RDI: 00000000ffffff9c
RBP: 0000000000000000 R08: 0000000000000002 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000009e82
R13: 0000000000000005 R14: 00007ffd6bd2df50 R15: 0000000000000000
Kernel Offset: disabled
Rebooting in 86400 seconds..

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-14 2019/11/17 02:59 linux-4.14.y 775d01b65b5d cdac920b .config log report syz C