syzbot


KCSAN: data-race in copy_page_from_iter_atomic / copy_page_to_iter

Status: auto-closed as invalid on 2021/12/04 07:27
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 401d, last: 401d

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

read to 0xffff888134227000 of 512 bytes by task 3437 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:805 [inline]
 copy_page_to_iter+0x2cb/0x950 lib/iov_iter.c:833
 filemap_read+0xee6/0x1220 mm/filemap.c:2683
 generic_file_read_iter+0x75/0x2c0 mm/filemap.c:2779
 blkdev_read_iter+0xb9/0xf0 block/fops.c:545
 call_read_iter include/linux/fs.h:2157 [inline]
 new_sync_read fs/read_write.c:404 [inline]
 vfs_read+0x66c/0x750 fs/read_write.c:485
 ksys_read+0xd9/0x190 fs/read_write.c:623
 __do_sys_read fs/read_write.c:633 [inline]
 __se_sys_read fs/read_write.c:631 [inline]
 __x64_sys_read+0x3e/0x50 fs/read_write.c:631
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

write to 0xffff888134227000 of 4096 bytes by task 24142 on cpu 1:
 instrument_copy_from_user include/linux/instrumented.h:136 [inline]
 copyin lib/iov_iter.c:167 [inline]
 copy_page_from_iter_atomic+0x32f/0xbb0 lib/iov_iter.c:922
 generic_perform_write+0x201/0x3e0 mm/filemap.c:3778
 __generic_file_write_iter+0x174/0x310 mm/filemap.c:3897
 blkdev_write_iter+0x1fd/0x2c0 block/fops.c:519
 call_write_iter include/linux/fs.h:2163 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0x7bc/0x900 fs/read_write.c:594
 ksys_write+0xd9/0x190 fs/read_write.c:647
 __do_sys_write fs/read_write.c:659 [inline]
 __se_sys_write fs/read_write.c:656 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:656
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 24142 Comm: syz-executor.3 Not tainted 5.15.0-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 2021/10/30 07:21 upstream a379fbbcb88b 098b5d53 .config log report info KCSAN: data-race in copy_page_from_iter_atomic / copy_page_to_iter
* Struck through repros no longer work on HEAD.