syzbot


WARNING in iomap_iter
Status: upstream: reported C repro on 2021/11/08 23:46
Reported-by: syzbot+a8e049cd3abd342936b6@syzkaller.appspotmail.com
First crash: 200d, last: 8d06h

Cause bisection: the issue happens on the oldest tested release (bisect log)
Crash: WARNING in iomap_apply (log)
Repro: C syz .config

Sample crash report:
------------[ cut here ]------------
WARNING: CPU: 0 PID: 49 at fs/iomap/iter.c:33 iomap_iter_done fs/iomap/iter.c:33 [inline]
WARNING: CPU: 0 PID: 49 at fs/iomap/iter.c:33 iomap_iter+0xd85/0x1110 fs/iomap/iter.c:78
Modules linked in:
CPU: 0 PID: 49 Comm: kworker/u4:2 Not tainted 5.17.0-rc8-syzkaller-00003-g56e337f2cf13 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: loop0 loop_rootcg_workfn
RIP: 0010:iomap_iter_done fs/iomap/iter.c:33 [inline]
RIP: 0010:iomap_iter+0xd85/0x1110 fs/iomap/iter.c:78
Code: fd ff ff e8 9d f2 d0 ff e9 f9 f9 ff ff e8 c3 0c 8a ff 0f 0b e9 87 f8 ff ff e8 b7 0c 8a ff 0f 0b e9 98 f7 ff ff e8 ab 0c 8a ff <0f> 0b e9 38 f7 ff ff e8 9f 0c 8a ff 0f 0b e9 64 f7 ff ff e8 93 0c
RSP: 0018:ffffc900011a7688 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffffc900011a7820 RCX: 0000000000000000
RDX: ffff888015fa4080 RSI: ffffffff81ede8e5 RDI: 0000000000000003
RBP: 00000fff80000000 R08: 00000fff80000000 R09: 000000000000000c
R10: ffffffff81ede01b R11: 000000000000003f R12: 0000000000000000
R13: ffffffff80000000 R14: ffffc900011a7848 R15: ffffc900011a7890
FS:  0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2f4d9e5130 CR3: 000000007b1f8000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __iomap_dio_rw+0x6b2/0x1ad0 fs/iomap/direct-io.c:589
 iomap_dio_rw+0x38/0x90 fs/iomap/direct-io.c:680
 ext4_dio_read_iter fs/ext4/file.c:77 [inline]
 ext4_file_read_iter+0x41c/0x5d0 fs/ext4/file.c:128
 call_read_iter include/linux/fs.h:2068 [inline]
 lo_rw_aio.isra.0+0xa99/0xc90 drivers/block/loop.c:454
 do_req_filebacked drivers/block/loop.c:498 [inline]
 loop_handle_cmd drivers/block/loop.c:1852 [inline]
 loop_process_work+0x92f/0x1db0 drivers/block/loop.c:1892
 process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307
 worker_thread+0x657/0x1110 kernel/workqueue.c:2454
 kthread+0x2e9/0x3a0 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

Fix bisection attempts:
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-selinux-root 2022/05/15 08:26 upstream 2fe1020d73ca 9e8eaa75 .config log report syz C
ci-upstream-kasan-gce-selinux-root 2022/04/15 04:21 upstream 028192fea1de 9e8eaa75 .config log report syz C
Crashes (12):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-selinux-root 2022/03/16 01:03 upstream 56e337f2cf13 9e8eaa75 .config log report syz C WARNING in iomap_iter
ci-upstream-kasan-gce-smack-root 2022/02/12 20:40 upstream 83e396641110 8b9ca619 .config log report syz C WARNING in iomap_iter
ci-upstream-linux-next-kasan-gce-root 2022/02/20 08:03 linux-next ef6b35306dd8 3cd800e4 .config log report syz C WARNING in iomap_iter
ci-upstream-kasan-gce 2022/05/16 15:25 upstream 42226c989789 744a39e2 .config log report info WARNING in iomap_iter
ci-upstream-kasan-gce-smack-root 2022/02/12 22:04 upstream 83e396641110 8b9ca619 .config log report info WARNING in iomap_iter
ci-upstream-kasan-gce 2022/01/10 22:00 upstream 133d9c53c9dc ddb0ab8c .config log report info WARNING in iomap_iter
ci-upstream-kasan-gce 2021/12/07 12:16 upstream f80ef9e49fdf 0230ba3e .config log report info WARNING in iomap_iter
ci-upstream-kasan-gce 2021/11/24 17:40 upstream 5d9f4cf36721 545ab074 .config log report info WARNING in iomap_iter
ci-qemu-upstream-386 2021/11/12 13:45 upstream 5833291ab6de 75b04091 .config log report info WARNING in iomap_iter
ci-upstream-kasan-gce-386 2021/11/04 23:43 upstream 7ddb58cb0eca 4c1be0be .config log report info WARNING in iomap_iter
ci-upstream-linux-next-kasan-gce-root 2022/02/12 21:54 linux-next ef6b35306dd8 8b9ca619 .config log report info WARNING in iomap_iter
ci-upstream-linux-next-kasan-gce-root 2021/11/28 05:40 linux-next f81e94e91878 63eeac02 .config log report info WARNING in iomap_iter