syzbot


KCSAN: data-race in xas_find_marked / xas_set_mark

Status: moderation: reported on 2019/12/05 04:45
Subsystems: fs mm
[Documentation on labels]
Reported-by: syzbot+238e9bb046564c2c4d4a@syzkaller.appspotmail.com
First crash: 2149d, last: 5h06m

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

write to 0xffff88811a0a3254 of 4 bytes by task 5043 on cpu 1:
 xa_mark_set lib/xarray.c:71 [inline]
 xas_set_mark+0x12b/0x140 lib/xarray.c:900
 __folio_start_writeback+0x1dd/0x440 mm/page-writeback.c:3071
 ext4_bio_write_folio+0x5ad/0x9f0 fs/ext4/page-io.c:583
 mpage_submit_folio fs/ext4/inode.c:2080 [inline]
 mpage_process_page_bufs+0x4a1/0x620 fs/ext4/inode.c:2191
 mpage_prepare_extent_to_map+0x786/0xc00 fs/ext4/inode.c:2736
 ext4_do_writepages+0xa05/0x2750 fs/ext4/inode.c:2929
 ext4_writepages+0x176/0x300 fs/ext4/inode.c:3025
 do_writepages+0x1c6/0x310 mm/page-writeback.c:2634
 filemap_fdatawrite_wbc mm/filemap.c:386 [inline]
 __filemap_fdatawrite_range mm/filemap.c:419 [inline]
 file_write_and_wait_range+0x156/0x2c0 mm/filemap.c:794
 generic_buffers_fsync_noflush+0x45/0x120 fs/buffer.c:609
 ext4_fsync_nojournal fs/ext4/fsync.c:88 [inline]
 ext4_sync_file+0x1ab/0x690 fs/ext4/fsync.c:147
 vfs_fsync_range+0x10a/0x130 fs/sync.c:187
 generic_write_sync include/linux/fs.h:3043 [inline]
 ext4_buffered_write_iter+0x34f/0x3c0 fs/ext4/file.c:305
 ext4_dio_write_iter fs/ext4/file.c:613 [inline]
 ext4_file_write_iter+0xdbf/0xf00 fs/ext4/file.c:721
 iter_file_splice_write+0x666/0xa60 fs/splice.c:738
 do_splice_from fs/splice.c:938 [inline]
 direct_splice_actor+0x156/0x2a0 fs/splice.c:1161
 splice_direct_to_actor+0x312/0x680 fs/splice.c:1105
 do_splice_direct_actor fs/splice.c:1204 [inline]
 do_splice_direct+0xda/0x150 fs/splice.c:1230
 do_sendfile+0x380/0x650 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64 fs/read_write.c:1417 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1417
 x64_sys_call+0x2bb0/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88811a0a3254 of 4 bytes by task 5037 on cpu 0:
 xa_marked include/linux/xarray.h:424 [inline]
 xas_find_marked+0x5dc/0x620 lib/xarray.c:1483
 find_get_entry+0x5d/0x380 mm/filemap.c:2039
 filemap_get_folios_tag+0x92/0x210 mm/filemap.c:2307
 mpage_prepare_extent_to_map+0x320/0xc00 fs/ext4/inode.c:2637
 ext4_do_writepages+0x708/0x2750 fs/ext4/inode.c:2877
 ext4_writepages+0x176/0x300 fs/ext4/inode.c:3025
 do_writepages+0x1c6/0x310 mm/page-writeback.c:2634
 filemap_fdatawrite_wbc mm/filemap.c:386 [inline]
 __filemap_fdatawrite_range mm/filemap.c:419 [inline]
 file_write_and_wait_range+0x156/0x2c0 mm/filemap.c:794
 generic_buffers_fsync_noflush+0x45/0x120 fs/buffer.c:609
 ext4_fsync_nojournal fs/ext4/fsync.c:88 [inline]
 ext4_sync_file+0x1ab/0x690 fs/ext4/fsync.c:147
 vfs_fsync_range+0x10a/0x130 fs/sync.c:187
 generic_write_sync include/linux/fs.h:3043 [inline]
 ext4_buffered_write_iter+0x34f/0x3c0 fs/ext4/file.c:305
 ext4_dio_write_iter fs/ext4/file.c:613 [inline]
 ext4_file_write_iter+0xdbf/0xf00 fs/ext4/file.c:721
 iter_file_splice_write+0x666/0xa60 fs/splice.c:738
 do_splice_from fs/splice.c:938 [inline]
 direct_splice_actor+0x156/0x2a0 fs/splice.c:1161
 splice_direct_to_actor+0x312/0x680 fs/splice.c:1105
 do_splice_direct_actor fs/splice.c:1204 [inline]
 do_splice_direct+0xda/0x150 fs/splice.c:1230
 do_sendfile+0x380/0x650 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64 fs/read_write.c:1417 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1417
 x64_sys_call+0x2bb0/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0a000021 -> 0x04000021

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 5037 Comm: syz.2.422 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
==================================================================
==================================================================
BUG: KCSAN: data-race in filemap_splice_read / filemap_splice_read

write to 0xffff8881166c0be8 of 8 bytes by task 5043 on cpu 1:
 filemap_splice_read+0x4f4/0x740 mm/filemap.c:3037
 ext4_file_splice_read+0x8f/0xb0 fs/ext4/file.c:158
 do_splice_read fs/splice.c:982 [inline]
 splice_direct_to_actor+0x26c/0x680 fs/splice.c:1086
 do_splice_direct_actor fs/splice.c:1204 [inline]
 do_splice_direct+0xda/0x150 fs/splice.c:1230
 do_sendfile+0x380/0x650 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64 fs/read_write.c:1417 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1417
 x64_sys_call+0x2bb0/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

write to 0xffff8881166c0be8 of 8 bytes by task 5037 on cpu 0:
 filemap_splice_read+0x4f4/0x740 mm/filemap.c:3037
 ext4_file_splice_read+0x8f/0xb0 fs/ext4/file.c:158
 do_splice_read fs/splice.c:982 [inline]
 splice_direct_to_actor+0x26c/0x680 fs/splice.c:1086
 do_splice_direct_actor fs/splice.c:1204 [inline]
 do_splice_direct+0xda/0x150 fs/splice.c:1230
 do_sendfile+0x380/0x650 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64 fs/read_write.c:1417 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1417
 x64_sys_call+0x2bb0/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x000000000000047f -> 0x0000000000000480

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 5037 Comm: syz.2.422 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
==================================================================

Crashes (2189):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/09/10 00:53 upstream 9dd1835ecda5 fdeaa69b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/09/09 20:22 upstream 9dd1835ecda5 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/09/08 20:43 upstream f777d1112ee5 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/09/08 09:33 upstream 76eeb9b8de98 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/09/07 19:42 upstream 6ab41fca2e80 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/09/07 05:37 upstream b236920731dd d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/09/06 09:24 upstream d1d10cea0895 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/09/06 04:22 upstream c8ed9b5c02a5 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/09/04 17:38 upstream 08b06c30a445 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/09/04 03:59 upstream b9a10f876409 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/09/03 20:30 upstream ec299e4dc21e 96a211bc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/09/02 22:14 upstream e6b9dce0aeeb 96a211bc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/09/02 14:02 upstream b320789d6883 96a211bc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/09/01 07:40 upstream b320789d6883 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/31 19:56 upstream 5c3b3264e585 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/31 03:34 upstream c8bc81a52d5a 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/30 12:26 upstream 11e7861d680c 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/29 23:00 upstream fb679c832b64 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/29 19:51 upstream fb679c832b64 3e1beec6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/29 11:23 upstream 07d9df80082b 3e1beec6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/27 19:44 upstream 39f90c196721 e12e5ba4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/26 17:13 upstream fab1beda7597 e12e5ba4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/26 06:05 upstream fab1beda7597 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/26 02:21 upstream b6add54ba618 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/24 16:46 upstream 69fd6b99b8f8 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/23 21:14 upstream 8d245acc1e88 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/23 08:21 upstream 6debb6904172 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/22 22:09 upstream cf6fc5eefc5b bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/22 15:13 upstream 3957a5720157 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/21 14:21 upstream 068a56e56fa8 3e79b825 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/21 11:45 upstream 068a56e56fa8 0b9605c8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/20 23:01 upstream 41cd3fd15263 0b9605c8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/20 17:32 upstream b19a97d57c15 0b9605c8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/20 02:52 upstream b19a97d57c15 79512909 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/19 22:13 upstream b19a97d57c15 254a27c1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/19 22:13 upstream b19a97d57c15 254a27c1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/19 14:01 upstream be48bcf004f9 254a27c1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/19 02:15 upstream be48bcf004f9 523f460e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/18 13:48 upstream c17b750b3ad9 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/17 23:17 upstream 8d561baae505 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/17 15:51 upstream 99bade344cfa 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/16 19:59 upstream 90d970cade8e 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/16 11:02 upstream dfd4b508c8c6 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/15 19:23 upstream ee94b00c1a64 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/15 03:59 upstream 24ea63ea3877 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/14 16:11 upstream 0cc53520e68b 5d8c2ac2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2025/08/14 11:04 upstream 0cc53520e68b 22ec1469 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_find_marked / xas_set_mark
2021/01/16 09:14 upstream 1d94330a437a 65a7a854 .config console log report info ci2-upstream-kcsan-gce
2019/10/23 02:27 https://github.com/google/ktsan.git kcsan 05f2236801fe d0686497 .config console log report ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.