syzbot


KCSAN: data-race in ext4_setattr / generic_file_buffered_read (2)

Status: auto-closed as invalid on 2020/11/02 08:43
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 748d, last: 733d
similar bugs (2):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in ext4_setattr / generic_file_buffered_read (3) 12 589d 663d 0/24 auto-closed as invalid on 2021/03/26 18:29
upstream KCSAN: data-race in ext4_setattr / generic_file_buffered_read 16 785d 834d 0/24 auto-closed as invalid on 2020/09/11 12:48

Sample crash report:
==================================================================
BUG: KCSAN: data-race in ext4_setattr / generic_file_buffered_read

write to 0xffff8880bb1e6640 of 8 bytes by task 20512 on cpu 0:
 i_size_write include/linux/fs.h:876 [inline]
 ext4_setattr+0xd63/0xec0 fs/ext4/inode.c:5386
 notify_change+0x7d7/0xa80 fs/attr.c:336
 do_truncate+0xe0/0x120 fs/open.c:64
 handle_truncate fs/namei.c:2909 [inline]
 do_open fs/namei.c:3255 [inline]
 path_openat+0x1a31/0x20a0 fs/namei.c:3368
 do_filp_open+0xbd/0x1d0 fs/namei.c:3395
 do_sys_openat2+0x33b/0x500 fs/open.c:1168
 do_sys_open fs/open.c:1184 [inline]
 __do_sys_creat fs/open.c:1258 [inline]
 __se_sys_creat fs/open.c:1252 [inline]
 __x64_sys_creat+0x62/0x80 fs/open.c:1252
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880bb1e6640 of 8 bytes by task 20510 on cpu 1:
 i_size_read include/linux/fs.h:854 [inline]
 generic_file_buffered_read+0x126d/0x1f60 mm/filemap.c:2266
 generic_file_read_iter+0x7d/0x3e0 mm/filemap.c:2503
 ext4_file_read_iter+0x2d8/0x420 fs/ext4/file.c:74
 call_read_iter include/linux/fs.h:1876 [inline]
 generic_file_splice_read+0x22b/0x310 fs/splice.c:312
 do_splice_to fs/splice.c:870 [inline]
 splice_direct_to_actor+0x2a8/0x660 fs/splice.c:950
 do_splice_direct+0xf2/0x170 fs/splice.c:1059
 do_sendfile+0x56a/0xba0 fs/read_write.c:1540
 __do_sys_sendfile64 fs/read_write.c:1601 [inline]
 __se_sys_sendfile64 fs/read_write.c:1587 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1587
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 20510 Comm: syz-executor.4 Not tainted 5.9.0-rc7-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 2020/09/28 08:35 upstream a1b8638ba132 6bfdbe89 .config log report info
ci2-upstream-kcsan-gce 2020/09/28 06:53 upstream a1b8638ba132 5dd8aee8 .config log report info
ci2-upstream-kcsan-gce 2020/09/14 00:17 upstream 84b134997212 2d3cdd63 .config log report
* Struck through repros no longer work on HEAD.