syzbot


KCSAN: data-race in ext4_write_end / filemap_read (3)

Status: auto-closed as invalid on 2022/01/06 21:12
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 373d, last: 365d
similar bugs (2):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in ext4_write_end / filemap_read (2) 1 467d 467d 0/24 auto-closed as invalid on 2021/09/27 01:17
upstream KCSAN: data-race in ext4_write_end / filemap_read 13 592d 639d 0/24 auto-closed as invalid on 2021/05/24 19:33

Sample crash report:
==================================================================
BUG: KCSAN: data-race in ext4_write_end / filemap_read

write to 0xffff88813b7b6818 of 8 bytes by task 17156 on cpu 1:
 i_size_write include/linux/fs.h:913 [inline]
 ext4_update_inode_size fs/ext4/ext4.h:3422 [inline]
 ext4_write_end+0x16d/0x710 fs/ext4/inode.c:1303
 ext4_da_write_end+0x6d/0x630 fs/ext4/inode.c:3026
 generic_perform_write+0x261/0x400 mm/filemap.c:3767
 ext4_buffered_write_iter+0x25b/0x380 fs/ext4/file.c:269
 ext4_file_write_iter+0x2e7/0x1200
 call_write_iter include/linux/fs.h:2162 [inline]
 do_iter_readv_writev+0x2de/0x380 fs/read_write.c:725
 do_iter_write+0x192/0x5c0 fs/read_write.c:851
 vfs_iter_write+0x4c/0x70 fs/read_write.c:892
 iter_file_splice_write+0x43a/0x790 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+0x345/0x650 fs/splice.c:891
 do_splice_direct+0x106/0x190 fs/splice.c:979
 do_sendfile+0x675/0xc40 fs/read_write.c:1245
 __do_sys_sendfile64 fs/read_write.c:1310 [inline]
 __se_sys_sendfile64 fs/read_write.c:1296 [inline]
 __x64_sys_sendfile64+0x102/0x140 fs/read_write.c:1296
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88813b7b6818 of 8 bytes by task 17166 on cpu 0:
 i_size_read include/linux/fs.h:891 [inline]
 filemap_read+0x1208/0x16d0 mm/filemap.c:2654
 generic_file_read_iter+0x72/0x2a0 mm/filemap.c:2792
 ext4_file_read_iter+0x1db/0x290
 call_read_iter include/linux/fs.h:2156 [inline]
 generic_file_splice_read+0x24f/0x330 fs/splice.c:311
 do_splice_to fs/splice.c:796 [inline]
 splice_direct_to_actor+0x2aa/0x650 fs/splice.c:870
 do_splice_direct+0x106/0x190 fs/splice.c:979
 do_sendfile+0x675/0xc40 fs/read_write.c:1245
 __do_sys_sendfile64 fs/read_write.c:1310 [inline]
 __se_sys_sendfile64 fs/read_write.c:1296 [inline]
 __x64_sys_sendfile64+0x102/0x140 fs/read_write.c:1296
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000000003ffc -> 0x0000000000004000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 17166 Comm: syz-executor.5 Tainted: G        W         5.16.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (3):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2021/12/02 21:05 upstream a51e3ac43ddb 61f86278 .config log report info KCSAN: data-race in ext4_write_end / filemap_read
ci2-upstream-kcsan-gce 2021/12/02 00:04 upstream 58e1100fdc59 61f86278 .config log report info KCSAN: data-race in ext4_write_end / filemap_read
ci2-upstream-kcsan-gce 2021/11/24 19:01 upstream 5f53fa508db0 545ab074 .config log report info KCSAN: data-race in ext4_write_end / filemap_read
* Struck through repros no longer work on HEAD.