syzbot


KCSAN: data-race in perf_trace_writeback_dirty_inode_template / writeback_sb_inodes

Status: moderation: reported on 2024/06/26 16:25
Subsystems: ext4
[Documentation on labels]
Reported-by: syzbot+038f522c05b2ff4cf692@syzkaller.appspotmail.com
First crash: 16d, last: 16d

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

write to 0xffff888106e933f0 of 8 bytes by task 36 on cpu 1:
 writeback_sb_inodes+0x31b/0xb20 fs/fs-writeback.c:1936
 wb_writeback+0x25e/0x720 fs/fs-writeback.c:2127
 wb_do_writeback fs/fs-writeback.c:2274 [inline]
 wb_workfn+0x1a8/0x940 fs/fs-writeback.c:2314
 process_one_work kernel/workqueue.c:3231 [inline]
 process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3312
 worker_thread+0x526/0x730 kernel/workqueue.c:3393
 kthread+0x1d1/0x210 kernel/kthread.c:389
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

read to 0xffff888106e933f0 of 8 bytes by task 6804 on cpu 0:
 perf_trace_writeback_dirty_inode_template+0x1aa/0x240 include/trace/events/writeback.h:96
 trace_writeback_dirty_inode include/trace/events/writeback.h:141 [inline]
 __mark_inode_dirty+0x605/0x7e0 fs/fs-writeback.c:2488
 mark_inode_dirty include/linux/fs.h:2404 [inline]
 dquot_alloc_space include/linux/quotaops.h:319 [inline]
 dquot_alloc_block include/linux/quotaops.h:336 [inline]
 ext4_mb_new_blocks+0x103e/0x2020 fs/ext4/mballoc.c:6185
 ext4_ext_map_blocks+0x10a1/0x33b0 fs/ext4/extents.c:4318
 ext4_map_blocks+0x72a/0xf50 fs/ext4/inode.c:623
 ext4_alloc_file_blocks+0x285/0x700 fs/ext4/extents.c:4495
 ext4_fallocate+0x782/0x1190 fs/ext4/extents.c:4792
 vfs_fallocate+0x380/0x3e0 fs/open.c:330
 do_vfs_ioctl+0x1481/0x1560 fs/ioctl.c:886
 __do_sys_ioctl fs/ioctl.c:905 [inline]
 __se_sys_ioctl+0x81/0x150 fs/ioctl.c:893
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:893
 x64_sys_call+0x1581/0x2d70 arch/x86/include/generated/asm/syscalls_64.h:17
 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: 0x0000000000020001 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 6804 Comm: syz.4.923 Not tainted 6.10.0-rc5-syzkaller-00018-g55027e689933 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/06/26 16:25 upstream 55027e689933 c6d33a01 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in perf_trace_writeback_dirty_inode_template / writeback_sb_inodes
* Struck through repros no longer work on HEAD.