syzbot


KCSAN: data-race in vfs_readlink / vfs_readlink (3)

Status: auto-closed as invalid on 2021/01/13 07:28
Reported-by: syzbot+1b4f8047c268f8c57bb9@syzkaller.appspotmail.com
First crash: 645d, last: 608d
similar bugs (3):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in vfs_readlink / vfs_readlink (4) 5 496d 564d 0/23 auto-closed as invalid on 2021/05/05 00:00
upstream KCSAN: data-race in vfs_readlink / vfs_readlink 2 762d 781d 0/23 auto-closed as invalid on 2020/08/11 15:56
upstream KCSAN: data-race in vfs_readlink / vfs_readlink (2) 1 715d 715d 0/23 auto-closed as invalid on 2020/09/28 03:37

Sample crash report:
==================================================================
BUG: KCSAN: data-race in vfs_readlink / vfs_readlink

read-write to 0xffff88812f198a02 of 2 bytes by task 9294 on cpu 1:
 vfs_readlink+0x203/0x250 fs/namei.c:4546
 do_readlinkat+0x170/0x200 fs/stat.c:419
 __do_sys_readlinkat fs/stat.c:434 [inline]
 __se_sys_readlinkat fs/stat.c:431 [inline]
 __x64_sys_readlinkat+0x4f/0x60 fs/stat.c:431
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88812f198a02 of 2 bytes by task 9304 on cpu 0:
 vfs_readlink+0x56/0x250 fs/namei.c:4538
 do_readlinkat+0x170/0x200 fs/stat.c:419
 __do_sys_readlinkat fs/stat.c:434 [inline]
 __se_sys_readlinkat fs/stat.c:431 [inline]
 __x64_sys_readlinkat+0x4f/0x60 fs/stat.c:431
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 9304 Comm: systemd-udevd Not tainted 5.10.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 9304 Comm: systemd-udevd Not tainted 5.10.0-rc7-syzkaller #0
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+0x116/0x15d lib/dump_stack.c:118
 panic+0x1e7/0x5fa kernel/panic.c:231
 kcsan_report+0x67b/0x680 kernel/kcsan/report.c:634
 kcsan_setup_watchpoint+0x46a/0x4d0 kernel/kcsan/core.c:568
 vfs_readlink+0x56/0x250 fs/namei.c:4538
 do_readlinkat+0x170/0x200 fs/stat.c:419
 __do_sys_readlinkat fs/stat.c:434 [inline]
 __se_sys_readlinkat fs/stat.c:431 [inline]
 __x64_sys_readlinkat+0x4f/0x60 fs/stat.c:431
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f85236990ba
Code: 48 8b 0d e1 bd 2b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 0b 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d ae bd 2b 00 f7 d8 64 89 01 48
RSP: 002b:00007ffdc33c9998 EFLAGS: 00000202 ORIG_RAX: 000000000000010b
RAX: ffffffffffffffda RBX: 0000564d53057b20 RCX: 00007f85236990ba
RDX: 0000564d53057b20 RSI: 00007ffdc33c9a20 RDI: 00000000ffffff9c
RBP: 0000000000000064 R08: 0000000000000000 R09: 0000000000000070
R10: 0000000000000063 R11: 0000000000000202 R12: 00007ffdc33c9a20
R13: 00000000ffffff9c R14: 00007ffdc33c99f0 R15: 0000000000000063
Kernel Offset: disabled
Rebooting in 86400 seconds..

Crashes (2):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2020/12/09 07:27 upstream 7d8761ba27fc 40cc414d .config log report info
ci2-upstream-kcsan-gce 2020/11/01 22:49 upstream 31f020064f9d 8bc4594f .config log report info