syzbot


KCSAN: data-race in filemap_read / ondemand_readahead

Status: auto-closed as invalid on 2021/09/29 19:15
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 508d, last: 464d

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

write to 0xffff888128b52db0 of 8 bytes by task 14222 on cpu 1:
 filemap_read+0xf2c/0x1220 mm/filemap.c:2609
 generic_file_read_iter+0x75/0x2c0 mm/filemap.c:2701
 call_read_iter include/linux/fs.h:2108 [inline]
 generic_file_splice_read+0x22a/0x310 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+0xf5/0x170 fs/splice.c:979
 do_sendfile+0x773/0xda0 fs/read_write.c:1260
 __do_sys_sendfile64 fs/read_write.c:1325 [inline]
 __se_sys_sendfile64 fs/read_write.c:1311 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1311
 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 0xffff888128b52db0 of 8 bytes by task 14210 on cpu 0:
 ondemand_readahead+0x59b/0x7b0 mm/readahead.c:507
 page_cache_sync_ra+0xaf/0xe0 mm/readahead.c:578
 page_cache_sync_readahead include/linux/pagemap.h:884 [inline]
 filemap_get_pages mm/filemap.c:2467 [inline]
 filemap_read+0x388/0x1220 mm/filemap.c:2550
 generic_file_read_iter+0x75/0x2c0 mm/filemap.c:2701
 call_read_iter include/linux/fs.h:2108 [inline]
 generic_file_splice_read+0x22a/0x310 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+0xf5/0x170 fs/splice.c:979
 do_sendfile+0x773/0xda0 fs/read_write.c:1260
 __do_sys_sendfile64 fs/read_write.c:1325 [inline]
 __se_sys_sendfile64 fs/read_write.c:1311 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1311
 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

value changed: 0x00000000000da000 -> 0x00000000000dae00

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 14210 Comm: syz-executor.1 Not tainted 5.14.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (4):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2021/08/25 19:08 upstream fe67f4dd8daa b599f2fc .config log report info KCSAN: data-race in filemap_read / ondemand_readahead
ci2-upstream-kcsan-gce 2021/08/24 18:38 upstream 6e764bcd1cf7 b599f2fc .config log report info KCSAN: data-race in filemap_read / ondemand_readahead
ci2-upstream-kcsan-gce 2021/08/08 08:28 upstream 85a90500f9a1 6972b106 .config log report info KCSAN: data-race in filemap_read / ondemand_readahead
ci2-upstream-kcsan-gce 2021/07/13 10:33 upstream 7fef2edf7cc7 f415556d .config log report info KCSAN: data-race in filemap_read / ondemand_readahead
* Struck through repros no longer work on HEAD.