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KCSAN: data-race in vga_arb_write / vga_arb_write (2)

Status: auto-obsoleted due to no activity on 2024/02/22 14:54
Subsystems: pci
[Documentation on labels]
Reported-by: syzbot+6a1aea810a45c686a583@syzkaller.appspotmail.com
First crash: 92d, last: 92d
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in vga_arb_write / vga_arb_write dri 1 814d 814d 0/26 auto-closed as invalid on 2022/03/02 16:50
upstream KCSAN: data-race in vga_arb_write / vga_arb_write (3) pci 1 10d 10d 0/26 moderation: reported on 2024/04/09 06:54

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

read to 0xffff88813acfac20 of 4 bytes by task 4261 on cpu 1:
 vga_arb_write+0xf06/0x1410 drivers/pci/vgaarb.c:1255
 vfs_write+0x27a/0x790 fs/read_write.c:588
 ksys_write+0xeb/0x1a0 fs/read_write.c:643
 __do_sys_write fs/read_write.c:655 [inline]
 __se_sys_write fs/read_write.c:652 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:652
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x59/0x120 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read-write to 0xffff88813acfac20 of 4 bytes by task 4257 on cpu 0:
 vga_arb_write+0x1216/0x1410 drivers/pci/vgaarb.c:1206
 vfs_write+0x27a/0x790 fs/read_write.c:588
 ksys_write+0xeb/0x1a0 fs/read_write.c:643
 __do_sys_write fs/read_write.c:655 [inline]
 __se_sys_write fs/read_write.c:652 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:652
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x59/0x120 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x0000001a -> 0x00000003

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 4257 Comm: syz-executor.5 Not tainted 6.7.0-syzkaller-11091-g296455ade1fd #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/01/18 14:53 upstream 296455ade1fd 239abf84 .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.