syzbot


KCSAN: data-race in copy_page_to_iter / ext4_mark_iloc_dirty

Status: auto-closed as invalid on 2021/09/30 09:26
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 457d, last: 457d
similar bugs (1):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in copy_page_to_iter / ext4_mark_iloc_dirty (2) 2 421d 421d 0/24 auto-closed as invalid on 2021/11/05 18:49

Sample crash report:
==================================================================
BUG: KCSAN: data-race in copy_page_to_iter / ext4_mark_iloc_dirty

write to 0xffff88811db4801c of 4 bytes by task 24229 on cpu 1:
 ext4_inode_blocks_set fs/ext4/inode.c:4926 [inline]
 ext4_do_update_inode fs/ext4/inode.c:5040 [inline]
 ext4_mark_iloc_dirty+0x23c/0x1750 fs/ext4/inode.c:5724
 __ext4_mark_inode_dirty+0x4db/0x5b0 fs/ext4/inode.c:5918
 ext4_write_end+0x420/0x820 fs/ext4/inode.c:1322
 ext4_da_write_end+0x93/0x730 fs/ext4/inode.c:3079
 generic_perform_write+0x22a/0x3c0 mm/filemap.c:3667
 ext4_buffered_write_iter+0x2f2/0x3f0 fs/ext4/file.c:269
 ext4_file_write_iter+0x2e7/0x11d0 fs/ext4/file.c:519
 call_write_iter include/linux/fs.h:2114 [inline]
 new_sync_write fs/read_write.c:518 [inline]
 vfs_write+0x69d/0x770 fs/read_write.c:605
 ksys_write+0xce/0x180 fs/read_write.c:658
 __do_sys_write fs/read_write.c:670 [inline]
 __se_sys_write fs/read_write.c:667 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:667
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88811db48000 of 1024 bytes by task 24213 on cpu 0:
 instrument_copy_to_user include/linux/instrumented.h:119 [inline]
 copyout lib/iov_iter.c:156 [inline]
 copy_page_to_iter_iovec lib/iov_iter.c:228 [inline]
 __copy_page_to_iter lib/iov_iter.c:801 [inline]
 copy_page_to_iter+0x2e1/0x940 lib/iov_iter.c:829
 filemap_read+0xef6/0x1220 mm/filemap.c:2605
 generic_file_read_iter+0x75/0x2c0 mm/filemap.c:2701
 blkdev_read_iter+0xb9/0xf0 fs/block_dev.c:1671
 call_read_iter include/linux/fs.h:2108 [inline]
 new_sync_read fs/read_write.c:415 [inline]
 vfs_read+0x565/0x5d0 fs/read_write.c:496
 ksys_read+0xce/0x180 fs/read_write.c:634
 __do_sys_read fs/read_write.c:644 [inline]
 __se_sys_read fs/read_write.c:642 [inline]
 __x64_sys_read+0x3e/0x50 fs/read_write.c:642
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 24213 Comm: systemd-udevd Not tainted 5.14.0-rc7-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 2021/08/26 09:25 upstream 73f3af7b4611 b599f2fc .config log report info KCSAN: data-race in copy_page_to_iter / ext4_mark_iloc_dirty
* Struck through repros no longer work on HEAD.