KCSAN: data-race in vga_arb_write / vga_arb_write (4)

Status: auto-obsoleted due to no activity on 2025/02/20 05:21
Subsystems: pci
[Documentation on labels]
Reported-by: syzbot+2699c160471dfeee2644@syzkaller.appspotmail.com
First crash: 610d, last: 610d
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [pci?] KCSAN: data-race in vga_arb_write / vga_arb_write (4) 1 (2) 2025/01/10 15:18
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in vga_arb_write / vga_arb_write dri 6 1 1674d 1674d 0/29 auto-closed as invalid on 2022/03/02 16:50
upstream KCSAN: data-race in vga_arb_write / vga_arb_write (3) pci 6 1 871d 871d 0/29 auto-obsoleted due to no activity on 2024/05/14 06:54
upstream KCSAN: data-race in vga_arb_write / vga_arb_write (2) pci 6 1 952d 952d 0/29 auto-obsoleted due to no activity on 2024/02/22 14:54

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

read-write to 0xffff88814f612424 of 4 bytes by task 17707 on cpu 0:
 vga_arb_write+0x11fa/0x1410 drivers/pci/vgaarb.c:1204
 vfs_write+0x281/0x920 fs/read_write.c:677
 ksys_write+0xe8/0x1b0 fs/read_write.c:731
 __do_sys_write fs/read_write.c:742 [inline]
 __se_sys_write fs/read_write.c:739 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:739
 x64_sys_call+0x287e/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read-write to 0xffff88814f612424 of 4 bytes by task 17708 on cpu 1:
 vga_arb_write+0xf45/0x1410 drivers/pci/vgaarb.c:1263
 vfs_write+0x281/0x920 fs/read_write.c:677
 ksys_write+0xe8/0x1b0 fs/read_write.c:731
 __do_sys_write fs/read_write.c:742 [inline]
 __se_sys_write fs/read_write.c:739 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:739
 x64_sys_call+0x287e/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000001 -> 0x00000007

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 17708 Comm: syz.4.3325 Not tainted 6.13.0-rc4-syzkaller-00012-g9b2ffa6148b1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/12/26 05:20 upstream 9b2ffa6148b1 444551c4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in vga_arb_write / vga_arb_write
* Struck through repros no longer work on HEAD.