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KCSAN: data-race in evdev_pass_values / evdev_read (13)

Status: moderation: reported on 2026/01/22 19:06
Subsystems: input
[Documentation on labels]
Reported-by: syzbot+1b327485934adf39955b@syzkaller.appspotmail.com
First crash: 50d, last: 17d
▶ ▼ ✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision Error
a4941a81-5b06-4f0e-988f-022857c1af48 assessment-kcsan Benign: ✅  Confident: ✅  ❓ KCSAN: data-race in evdev_pass_values / evdev_read (13) 2026/02/25 03:28 2026/02/25 03:28 2026/02/25 03:30 305c0ec5cd886e2d13738e28e1b2df9b0ec20fc9
8857af3b-2ee2-4a17-87ec-c00048e38f40 assessment-kcsan 💥 KCSAN: data-race in evdev_pass_values / evdev_read (13) 2026/01/23 07:54 2026/01/23 07:54 2026/01/23 07:54 499a21815ec0ab13dbfc80e05fc32aadbc482145 failed to run ["make" "KERNELVERSION=syzkaller" "KERNELRELEASE=syzkaller" "LOCALVERSION=-syzkaller" "-j" "16" "ARCH=x86_64" "CC=ccache clang" "LD=ld.lld" "O=/usr/local/google/home/dvyukov/syzkaller/workdir/cache/build/08a402c00dcf920e418ce72eca15117888c80f58" "bzImage" "compile_commands.json"]: exit status 2
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[PATCH] Input: evdev: fix data race in evdev_read() and evdev_poll() 2 (2) 2026/02/26 15:17
▶ ▼ Similar bugs (12)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in evdev_pass_values / evdev_read (9) input 6 2 638d 649d 0/29 auto-obsoleted due to no activity on 2024/07/18 19:14
upstream KCSAN: data-race in evdev_pass_values / evdev_read (6) input 6 5 1162d 1188d 0/29 auto-obsoleted due to no activity on 2023/02/12 16:10
upstream KCSAN: data-race in evdev_pass_values / evdev_read (5) input 6 1 1230d 1230d 0/29 auto-obsoleted due to no activity on 2022/12/04 22:10
upstream KCSAN: data-race in evdev_pass_values / evdev_read input 6 1 2048d 2048d 0/29 auto-closed as invalid on 2020/09/08 04:08
upstream KCSAN: data-race in evdev_pass_values / evdev_read (2) input 6 1 1801d 1801d 0/29 auto-closed as invalid on 2021/05/12 19:26
upstream KCSAN: data-race in evdev_pass_values / evdev_read (10) input 6 1 548d 548d 0/29 auto-obsoleted due to no activity on 2024/10/16 22:12
upstream KCSAN: data-race in evdev_pass_values / evdev_read (4) input 6 4 1273d 1312d 0/29 auto-obsoleted due to no activity on 2022/10/23 08:11
upstream KCSAN: data-race in evdev_pass_values / evdev_read (7) input 6 28 977d 1051d 0/29 auto-obsoleted due to no activity on 2023/08/14 19:50
upstream KCSAN: data-race in evdev_pass_values / evdev_read (11) input 6 1 371d 371d 0/29 auto-obsoleted due to no activity on 2025/05/03 03:24
upstream KCSAN: data-race in evdev_pass_values / evdev_read (8) input 6 16 858d 825d 0/29 auto-obsoleted due to no activity on 2023/12/24 00:01
upstream KCSAN: data-race in evdev_pass_values / evdev_read (12) input 6 4 113d 225d 0/29 auto-obsoleted due to no activity on 2026/01/16 02:34
upstream KCSAN: data-race in evdev_pass_values / evdev_read (3) input 6 78 1353d 1397d 0/29 auto-closed as invalid on 2022/08/03 23:33

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

write to 0xffff888104a11808 of 4 bytes by task 27698 on cpu 0:
 __pass_event drivers/input/evdev.c:239 [inline]
 evdev_pass_values+0x387/0x4e0 drivers/input/evdev.c:278
 evdev_events+0x8e/0xd0 drivers/input/evdev.c:306
 input_pass_values+0x123/0x390 drivers/input/input.c:128
 input_event_dispose+0x248/0x320 drivers/input/input.c:342
 input_handle_event+0x9e8/0xa20 drivers/input/input.c:370
 input_inject_event+0xbc/0x120 drivers/input/input.c:424
 evdev_write+0x224/0x2b0 drivers/input/evdev.c:528
 vfs_write+0x269/0x9f0 fs/read_write.c:686
 ksys_write+0xdc/0x1a0 fs/read_write.c:740
 __do_sys_write fs/read_write.c:751 [inline]
 __se_sys_write fs/read_write.c:748 [inline]
 __x64_sys_write+0x40/0x50 fs/read_write.c:748
 x64_sys_call+0x27e1/0x3020 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888104a11808 of 4 bytes by task 2985 on cpu 1:
 evdev_read+0x157/0x5e0 drivers/input/evdev.c:572
 vfs_read+0x1ab/0x7f0 fs/read_write.c:572
 ksys_read+0xdc/0x1a0 fs/read_write.c:717
 __do_sys_read fs/read_write.c:726 [inline]
 __se_sys_read fs/read_write.c:724 [inline]
 __x64_sys_read+0x40/0x50 fs/read_write.c:724
 x64_sys_call+0x2886/0x3020 arch/x86/include/generated/asm/syscalls_64.h:1
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000e -> 0x00000010

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 2985 Comm: acpid Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/25 01:03 upstream 7dff99b35460 787dfb7c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in evdev_pass_values / evdev_read
2026/01/22 19:06 upstream a66191c590b3 82c9c083 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in evdev_pass_values / evdev_read
* Struck through repros no longer work on HEAD.