syzbot


KCSAN: data-race in ext4_dio_write_end_io / ondemand_readahead (3)

Status: closed as invalid on 2022/05/13 11:20
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 211d, last: 211d
similar bugs (2):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in ext4_dio_write_end_io / ondemand_readahead 1 517d 517d 0/24 auto-closed as invalid on 2021/08/11 00:47
upstream KCSAN: data-race in ext4_dio_write_end_io / ondemand_readahead (2) 1 305d 305d 0/24 auto-closed as invalid on 2022/03/10 18:06

Sample crash report:
==================================================================
BUG: KCSAN: data-race in ext4_dio_write_end_io / ondemand_readahead

write to 0xffff88813553f608 of 8 bytes by task 18345 on cpu 0:
 i_size_write include/linux/fs.h:878 [inline]
 ext4_dio_write_end_io+0xd3/0x100 fs/ext4/file.c:399
 iomap_dio_complete+0xb8/0x3e0 fs/iomap/direct-io.c:79
 iomap_dio_rw+0x56/0x80 fs/iomap/direct-io.c:684
 ext4_dio_write_iter fs/ext4/file.c:566 [inline]
 ext4_file_write_iter+0xaa1/0x1210 fs/ext4/file.c:677
 do_iter_readv_writev+0x27b/0x300
 do_iter_write+0x16f/0x5c0 fs/read_write.c:852
 vfs_iter_write+0x4c/0x70 fs/read_write.c:893
 iter_file_splice_write+0x44a/0x7c0 fs/splice.c:689
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:936
 splice_direct_to_actor+0x345/0x660 fs/splice.c:891
 do_splice_direct+0xfb/0x180 fs/splice.c:979
 do_sendfile+0x3ad/0x900 fs/read_write.c:1246
 __do_sys_sendfile64 fs/read_write.c:1311 [inline]
 __se_sys_sendfile64 fs/read_write.c:1297 [inline]
 __x64_sys_sendfile64+0x10c/0x150 fs/read_write.c:1297
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88813553f608 of 8 bytes by task 18354 on cpu 1:
 i_size_read include/linux/fs.h:856 [inline]
 do_page_cache_ra mm/readahead.c:278 [inline]
 page_cache_ra_order mm/readahead.c:546 [inline]
 ondemand_readahead+0x57f/0x780 mm/readahead.c:668
 page_cache_async_ra+0x134/0x140 mm/readahead.c:717
 filemap_readahead mm/filemap.c:2568 [inline]
 filemap_get_pages mm/filemap.c:2608 [inline]
 filemap_read+0x4f3/0x1400 mm/filemap.c:2679
 generic_file_read_iter+0x72/0x320 mm/filemap.c:2825
 ext4_file_read_iter+0x1e9/0x2a0
 call_read_iter include/linux/fs.h:2044 [inline]
 generic_file_splice_read+0x1de/0x2c0 fs/splice.c:311
 do_splice_to fs/splice.c:796 [inline]
 splice_direct_to_actor+0x2ac/0x660 fs/splice.c:870
 do_splice_direct+0xfb/0x180 fs/splice.c:979
 do_sendfile+0x3ad/0x900 fs/read_write.c:1246
 __do_sys_sendfile64 fs/read_write.c:1311 [inline]
 __se_sys_sendfile64 fs/read_write.c:1297 [inline]
 __x64_sys_sendfile64+0x10c/0x150 fs/read_write.c:1297
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000000002a3000 -> 0x00000000002b2000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 18354 Comm: syz-executor.0 Not tainted 5.18.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2022/05/09 12:19 upstream c5eb0a61238d 8b277b8e .config log report info KCSAN: data-race in ext4_dio_write_end_io / ondemand_readahead
* Struck through repros no longer work on HEAD.