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* [syzbot] [netfs?] INFO: task hung in vfs_utimes (3)
@ 2025-09-17 22:54 syzbot
  2025-09-19  0:47 ` syzbot
                   ` (2 more replies)
  0 siblings, 3 replies; 10+ messages in thread
From: syzbot @ 2025-09-17 22:54 UTC (permalink / raw)
  To: dhowells, linux-fsdevel, linux-kernel, netfs, pc, syzkaller-bugs

Hello,

syzbot found the following issue on:

HEAD commit:    46a51f4f5eda Merge tag 'for-v6.17-rc' of git://git.kernel...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=144cce42580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8f01d8629880e620
dashboard link: https://syzkaller.appspot.com/bug?extid=3815dce0acab6c55984e
compiler:       gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17692f62580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1361f47c580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c4f63dbf3edb/disk-46a51f4f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b110f6d26eda/vmlinux-46a51f4f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a0b5f2118cec/bzImage-46a51f4f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3815dce0acab6c55984e@syzkaller.appspotmail.com

INFO: task syz.0.17:6022 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.17        state:D stack:28976 pid:6022  tgid:6020  ppid:5973   task_flags:0x400040 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6961
 __schedule_loop kernel/sched/core.c:7043 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:7058
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7115
 rwsem_down_write_slowpath+0x524/0x1310 kernel/locking/rwsem.c:1185
 __down_write_common kernel/locking/rwsem.c:1317 [inline]
 __down_write kernel/locking/rwsem.c:1326 [inline]
 down_write+0x1d6/0x200 kernel/locking/rwsem.c:1591
 inode_lock include/linux/fs.h:870 [inline]
 vfs_utimes+0x3b7/0x820 fs/utimes.c:65
 do_utimes_path fs/utimes.c:99 [inline]
 do_utimes fs/utimes.c:140 [inline]
 __do_sys_utime fs/utimes.c:221 [inline]
 __se_sys_utime fs/utimes.c:210 [inline]
 __x64_sys_utime+0x1e2/0x2c0 fs/utimes.c:210
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fabd158eba9
RSP: 002b:00007fabd0bdd038 EFLAGS: 00000246 ORIG_RAX: 0000000000000084
RAX: ffffffffffffffda RBX: 00007fabd17d6090 RCX: 00007fabd158eba9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00002000000000c0
RBP: 00007fabd1611e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fabd17d6128 R14: 00007fabd17d6090 R15: 00007ffd32e714b8
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8e5c15a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e5c15a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8e5c15a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775
2 locks held by getty/5612:
 #0: ffff88814d96d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222
2 locks held by syz.0.17/6021:
 #0: ffff8880787b6428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153
 #1: ffff88805bdb8148 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188
2 locks held by syz.0.17/6022:
 #0: ffff8880787b6428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36
 #1: ffff88805bdb8148 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline]
 #1: ffff88805bdb8148 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65
2 locks held by syz.1.18/6047:
 #0: ffff888074228428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153
 #1: ffff88805bdb87b8 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188
2 locks held by syz.1.18/6049:
 #0: ffff888074228428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36
 #1: ffff88805bdb87b8 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline]
 #1: ffff88805bdb87b8 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65
2 locks held by syz.2.20/6077:
 #0: ffff888032842428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153
 #1: ffff88805f8c07b8 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188
2 locks held by syz.2.20/6079:
 #0: ffff888032842428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36
 #1: ffff88805f8c07b8 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline]
 #1: ffff88805f8c07b8 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65
2 locks held by syz.3.21/6103:
 #0: ffff888078172428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153
 #1: ffff88805bdb8e28 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188
2 locks held by syz.3.21/6104:
 #0: ffff888078172428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36
 #1: ffff88805bdb8e28 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline]
 #1: ffff88805bdb8e28 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65
2 locks held by syz.4.22/6133:
 #0: ffff888076a00428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153
 #1: ffff88805bdb9498 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188
2 locks held by syz.4.22/6134:
 #0: ffff888076a00428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36
 #1: ffff88805bdb9498 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline]
 #1: ffff88805bdb9498 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65
2 locks held by syz.5.23/6168:
 #0: ffff88806b6da428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153
 #1: ffff88805bdb9b08 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188
2 locks held by syz.5.23/6169:
 #0: ffff88806b6da428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36
 #1: ffff88805bdb9b08 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline]
 #1: ffff88805bdb9b08 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65
2 locks held by syz.6.26/6203:
 #0: ffff888059288428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153
 #1: ffff88805bdba178 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188
2 locks held by syz.6.26/6204:
 #0: ffff888059288428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36
 #1: ffff88805bdba178 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline]
 #1: ffff88805bdba178 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65
2 locks held by syz.7.27/6232:
 #0: ffff88805cc2a428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153
 #1: ffff88805f8c1b08 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188
2 locks held by syz.7.27/6234:
 #0: ffff88805cc2a428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36
 #1: ffff88805f8c1b08 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline]
 #1: ffff88805f8c1b08 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65
2 locks held by syz.8.28/6264:
 #0: ffff88807b296428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153
 #1: ffff88805bdba7e8 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188
2 locks held by syz.8.28/6265:
 #0: ffff88807b296428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36
 #1: ffff88805bdba7e8 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline]
 #1: ffff88805bdba7e8 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65
2 locks held by syz.9.29/6301:
 #0: ffff88805912a428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153
 #1: ffff88805f8c1498 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188
2 locks held by syz.9.29/6302:
 #0: ffff88805912a428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36
 #1: ffff88805f8c1498 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline]
 #1: ffff88805f8c1498 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65

=============================================

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline]
 watchdog+0xf0e/0x1260 kernel/hung_task.c:491
 kthread+0x3c2/0x780 kernel/kthread.c:463
 ret_from_fork+0x56a/0x730 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 49 Comm: kworker/u8:3 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: bat_events batadv_nc_worker
RIP: 0010:iterate_chain_key kernel/locking/lockdep.c:451 [inline]
RIP: 0010:__lock_acquire+0x642/0x1ce0 kernel/locking/lockdep.c:5225
Code: 08 45 85 d2 0f 85 6f 04 00 00 4c 89 e7 89 4c 24 08 e8 92 ac ff ff 8b 4c 24 08 48 83 78 40 00 0f 84 c2 0a 00 00 0f b7 44 24 10 <8b> 7c 24 28 44 8b 74 24 20 c1 e0 0d 66 0b 04 24 98 29 f8 8b 7c 24
RSP: 0018:ffffc90000b97958 EFLAGS: 00000086
RAX: 0000000000000700 RBX: ffff888022ae2f30 RCX: 00000000748bd351
RDX: 0000000000000000 RSI: ffff888022ae2f80 RDI: ffff888022ae2f80
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000002 R11: 0000000000000000 R12: ffff888022ae2f80
R13: ffff888022ae2440 R14: 0000000000000002 R15: 0000000000000003
FS:  0000000000000000(0000) GS:ffff8881247b2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055fb93cf9be0 CR3: 000000000e380000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 lock_acquire kernel/locking/lockdep.c:5868 [inline]
 lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
 _raw_spin_lock_bh+0x33/0x40 kernel/locking/spinlock.c:178
 spin_lock_bh include/linux/spinlock.h:356 [inline]
 batadv_nc_purge_paths+0xd9/0x3a0 net/batman-adv/network-coding.c:442
 batadv_nc_worker+0x958/0x1030 net/batman-adv/network-coding.c:722
 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3236
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c2/0x780 kernel/kthread.c:463
 ret_from_fork+0x56a/0x730 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [syzbot] [netfs?] INFO: task hung in vfs_utimes (3)
  2025-09-17 22:54 [syzbot] [netfs?] INFO: task hung in vfs_utimes (3) syzbot
@ 2025-09-19  0:47 ` syzbot
  2025-09-19  2:18   ` Hillf Danton
  2025-09-19  7:14   ` Oleg Nesterov
  2025-09-19  1:29 ` Forwarded: " syzbot
  2025-09-19  6:48 ` Oleg Nesterov
  2 siblings, 2 replies; 10+ messages in thread
From: syzbot @ 2025-09-19  0:47 UTC (permalink / raw)
  To: brauner, dhowells, jack, jlayton, linux-fsdevel, linux-kernel,
	netfs, oleg, pc, syzkaller-bugs, viro

syzbot has bisected this issue to:

commit aaec5a95d59615523db03dd53c2052f0a87beea7
Author: Oleg Nesterov <oleg@redhat.com>
Date:   Thu Jan 2 14:07:15 2025 +0000

    pipe_read: don't wake up the writer if the pipe is still full

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=175fa534580000
start commit:   46a51f4f5eda Merge tag 'for-v6.17-rc' of git://git.kernel...
git tree:       upstream
final oops:     https://syzkaller.appspot.com/x/report.txt?x=14dfa534580000
console output: https://syzkaller.appspot.com/x/log.txt?x=10dfa534580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8f01d8629880e620
dashboard link: https://syzkaller.appspot.com/bug?extid=3815dce0acab6c55984e
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17692f62580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1361f47c580000

Reported-by: syzbot+3815dce0acab6c55984e@syzkaller.appspotmail.com
Fixes: aaec5a95d596 ("pipe_read: don't wake up the writer if the pipe is still full")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

^ permalink raw reply	[flat|nested] 10+ messages in thread

* Forwarded: Re: [syzbot] [netfs?] INFO: task hung in vfs_utimes (3)
  2025-09-17 22:54 [syzbot] [netfs?] INFO: task hung in vfs_utimes (3) syzbot
  2025-09-19  0:47 ` syzbot
@ 2025-09-19  1:29 ` syzbot
  2025-09-19  6:48 ` Oleg Nesterov
  2 siblings, 0 replies; 10+ messages in thread
From: syzbot @ 2025-09-19  1:29 UTC (permalink / raw)
  To: linux-kernel

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.

***

Subject: Re: [syzbot] [netfs?] INFO: task hung in vfs_utimes (3)
Author: lizhi.xu@windriver.com

#syz test

diff --git a/fs/pipe.c b/fs/pipe.c
index 731622d0738d..ca7a6746f8ef 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -356,8 +356,8 @@ anon_pipe_read(struct kiocb *iocb, struct iov_iter *to)
 				buf->len = 0;
 			}
 
+			wake_writer |= pipe_full(head, tail, pipe->max_usage);
 			if (!buf->len) {
-				wake_writer |= pipe_full(head, tail, pipe->max_usage);
 				tail = pipe_update_tail(pipe, buf, tail);
 			}
 			total_len -= chars;

^ permalink raw reply related	[flat|nested] 10+ messages in thread

* Re: [syzbot] [netfs?] INFO: task hung in vfs_utimes (3)
       [not found] <20250919012918.213435-1-lizhi.xu@windriver.com>
@ 2025-09-19  2:04 ` syzbot
  0 siblings, 0 replies; 10+ messages in thread
From: syzbot @ 2025-09-19  2:04 UTC (permalink / raw)
  To: linux-kernel, lizhi.xu, syzkaller-bugs

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+3815dce0acab6c55984e@syzkaller.appspotmail.com
Tested-by: syzbot+3815dce0acab6c55984e@syzkaller.appspotmail.com

Tested on:

commit:         097a6c33 Merge tag 'trace-rv-v6.17-rc5' of git://git.k..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17bf1c7c580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8f01d8629880e620
dashboard link: https://syzkaller.appspot.com/bug?extid=3815dce0acab6c55984e
compiler:       gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=10bae0e2580000

Note: testing is done by a robot and is best-effort only.

^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [syzbot] [netfs?] INFO: task hung in vfs_utimes (3)
  2025-09-19  0:47 ` syzbot
@ 2025-09-19  2:18   ` Hillf Danton
  2025-09-19  2:44     ` syzbot
  2025-09-19  7:14   ` Oleg Nesterov
  1 sibling, 1 reply; 10+ messages in thread
From: Hillf Danton @ 2025-09-19  2:18 UTC (permalink / raw)
  To: syzbot; +Cc: linux-kernel, syzkaller-bugs

> Date: Thu, 18 Sep 2025 17:47:03 -0700	[thread overview]
> syzbot has bisected this issue to:
> 
> commit aaec5a95d59615523db03dd53c2052f0a87beea7
> Author: Oleg Nesterov <oleg@redhat.com>
> Date:   Thu Jan 2 14:07:15 2025 +0000
> 
>     pipe_read: don't wake up the writer if the pipe is still full
> 
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=175fa534580000
> start commit:   46a51f4f5eda Merge tag 'for-v6.17-rc' of git://git.kernel...
> git tree:       upstream
> final oops:     https://syzkaller.appspot.com/x/report.txt?x=14dfa534580000
> console output: https://syzkaller.appspot.com/x/log.txt?x=10dfa534580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=8f01d8629880e620
> dashboard link: https://syzkaller.appspot.com/bug?extid=3815dce0acab6c55984e
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17692f62580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1361f47c580000

Test Oleg's fix.

#syz test upstream  master

--- x/net/9p/trans_fd.c
+++ y/net/9p/trans_fd.c
@@ -666,7 +666,6 @@ static void p9_poll_mux(struct p9_conn *
 
 static int p9_fd_request(struct p9_client *client, struct p9_req_t *req)
 {
-	__poll_t n;
 	int err;
 	struct p9_trans_fd *ts = client->trans;
 	struct p9_conn *m = &ts->conn;
@@ -686,14 +685,7 @@ static int p9_fd_request(struct p9_clien
 	list_add_tail(&req->req_list, &m->unsent_req_list);
 	spin_unlock(&m->req_lock);
 
-	if (test_and_clear_bit(Wpending, &m->wsched))
-		n = EPOLLOUT;
-	else
-		n = p9_fd_poll(m->client, NULL, NULL);
-
-	if (n & EPOLLOUT && !test_and_set_bit(Wworksched, &m->wsched))
-		schedule_work(&m->wq);
-
+	p9_poll_mux(m);
 	return 0;
 }
 
--

^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [syzbot] [netfs?] INFO: task hung in vfs_utimes (3)
  2025-09-19  2:18   ` Hillf Danton
@ 2025-09-19  2:44     ` syzbot
  0 siblings, 0 replies; 10+ messages in thread
From: syzbot @ 2025-09-19  2:44 UTC (permalink / raw)
  To: hdanton, linux-kernel, syzkaller-bugs

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+3815dce0acab6c55984e@syzkaller.appspotmail.com
Tested-by: syzbot+3815dce0acab6c55984e@syzkaller.appspotmail.com

Tested on:

commit:         097a6c33 Merge tag 'trace-rv-v6.17-rc5' of git://git.k..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15ccc712580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8f01d8629880e620
dashboard link: https://syzkaller.appspot.com/bug?extid=3815dce0acab6c55984e
compiler:       gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1574c712580000

Note: testing is done by a robot and is best-effort only.

^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [syzbot] [netfs?] INFO: task hung in vfs_utimes (3)
  2025-09-17 22:54 [syzbot] [netfs?] INFO: task hung in vfs_utimes (3) syzbot
  2025-09-19  0:47 ` syzbot
  2025-09-19  1:29 ` Forwarded: " syzbot
@ 2025-09-19  6:48 ` Oleg Nesterov
  2025-09-19 12:22   ` Hillf Danton
  2025-09-19 13:25   ` Dominique Martinet
  2 siblings, 2 replies; 10+ messages in thread
From: Oleg Nesterov @ 2025-09-19  6:48 UTC (permalink / raw)
  To: syzbot, Dominique Martinet, Hillf Danton
  Cc: dhowells, linux-fsdevel, linux-kernel, netfs, pc, syzkaller-bugs

Dominique,

according to

	https://lore.kernel.org/all/20250919021852.7157-1-hdanton@sina.com/
	https://lore.kernel.org/all/68ccc372.050a0220.28a605.0016.GAE@google.com/

this is yet another issue seems to be fixed by

	[PATCH] 9p/trans_fd: p9_fd_request: kick rx thread if EPOLLIN
	https://lore.kernel.org/all/20250819161013.GB11345@redhat.com/

are you going to apply it?

Hillf, thanks a lot!

Oleg.

On 09/17, syzbot wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    46a51f4f5eda Merge tag 'for-v6.17-rc' of git://git.kernel...
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=144cce42580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=8f01d8629880e620
> dashboard link: https://syzkaller.appspot.com/bug?extid=3815dce0acab6c55984e
> compiler:       gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17692f62580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1361f47c580000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/c4f63dbf3edb/disk-46a51f4f.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/b110f6d26eda/vmlinux-46a51f4f.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/a0b5f2118cec/bzImage-46a51f4f.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+3815dce0acab6c55984e@syzkaller.appspotmail.com
>
> INFO: task syz.0.17:6022 blocked for more than 143 seconds.
>       Not tainted syzkaller #0
> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> task:syz.0.17        state:D stack:28976 pid:6022  tgid:6020  ppid:5973   task_flags:0x400040 flags:0x00004004
> Call Trace:
>  <TASK>
>  context_switch kernel/sched/core.c:5357 [inline]
>  __schedule+0x1190/0x5de0 kernel/sched/core.c:6961
>  __schedule_loop kernel/sched/core.c:7043 [inline]
>  schedule+0xe7/0x3a0 kernel/sched/core.c:7058
>  schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7115
>  rwsem_down_write_slowpath+0x524/0x1310 kernel/locking/rwsem.c:1185
>  __down_write_common kernel/locking/rwsem.c:1317 [inline]
>  __down_write kernel/locking/rwsem.c:1326 [inline]
>  down_write+0x1d6/0x200 kernel/locking/rwsem.c:1591
>  inode_lock include/linux/fs.h:870 [inline]
>  vfs_utimes+0x3b7/0x820 fs/utimes.c:65
>  do_utimes_path fs/utimes.c:99 [inline]
>  do_utimes fs/utimes.c:140 [inline]
>  __do_sys_utime fs/utimes.c:221 [inline]
>  __se_sys_utime fs/utimes.c:210 [inline]
>  __x64_sys_utime+0x1e2/0x2c0 fs/utimes.c:210
>  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
>  do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7fabd158eba9
> RSP: 002b:00007fabd0bdd038 EFLAGS: 00000246 ORIG_RAX: 0000000000000084
> RAX: ffffffffffffffda RBX: 00007fabd17d6090 RCX: 00007fabd158eba9
> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00002000000000c0
> RBP: 00007fabd1611e19 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007fabd17d6128 R14: 00007fabd17d6090 R15: 00007ffd32e714b8
>  </TASK>
>
> Showing all locks held in the system:
> 1 lock held by khungtaskd/31:
>  #0: ffffffff8e5c15a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
>  #0: ffffffff8e5c15a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
>  #0: ffffffff8e5c15a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775
> 2 locks held by getty/5612:
>  #0: ffff88814d96d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
>  #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222
> 2 locks held by syz.0.17/6021:
>  #0: ffff8880787b6428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153
>  #1: ffff88805bdb8148 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188
> 2 locks held by syz.0.17/6022:
>  #0: ffff8880787b6428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36
>  #1: ffff88805bdb8148 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline]
>  #1: ffff88805bdb8148 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65
> 2 locks held by syz.1.18/6047:
>  #0: ffff888074228428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153
>  #1: ffff88805bdb87b8 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188
> 2 locks held by syz.1.18/6049:
>  #0: ffff888074228428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36
>  #1: ffff88805bdb87b8 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline]
>  #1: ffff88805bdb87b8 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65
> 2 locks held by syz.2.20/6077:
>  #0: ffff888032842428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153
>  #1: ffff88805f8c07b8 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188
> 2 locks held by syz.2.20/6079:
>  #0: ffff888032842428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36
>  #1: ffff88805f8c07b8 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline]
>  #1: ffff88805f8c07b8 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65
> 2 locks held by syz.3.21/6103:
>  #0: ffff888078172428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153
>  #1: ffff88805bdb8e28 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188
> 2 locks held by syz.3.21/6104:
>  #0: ffff888078172428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36
>  #1: ffff88805bdb8e28 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline]
>  #1: ffff88805bdb8e28 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65
> 2 locks held by syz.4.22/6133:
>  #0: ffff888076a00428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153
>  #1: ffff88805bdb9498 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188
> 2 locks held by syz.4.22/6134:
>  #0: ffff888076a00428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36
>  #1: ffff88805bdb9498 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline]
>  #1: ffff88805bdb9498 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65
> 2 locks held by syz.5.23/6168:
>  #0: ffff88806b6da428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153
>  #1: ffff88805bdb9b08 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188
> 2 locks held by syz.5.23/6169:
>  #0: ffff88806b6da428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36
>  #1: ffff88805bdb9b08 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline]
>  #1: ffff88805bdb9b08 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65
> 2 locks held by syz.6.26/6203:
>  #0: ffff888059288428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153
>  #1: ffff88805bdba178 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188
> 2 locks held by syz.6.26/6204:
>  #0: ffff888059288428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36
>  #1: ffff88805bdba178 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline]
>  #1: ffff88805bdba178 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65
> 2 locks held by syz.7.27/6232:
>  #0: ffff88805cc2a428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153
>  #1: ffff88805f8c1b08 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188
> 2 locks held by syz.7.27/6234:
>  #0: ffff88805cc2a428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36
>  #1: ffff88805f8c1b08 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline]
>  #1: ffff88805f8c1b08 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65
> 2 locks held by syz.8.28/6264:
>  #0: ffff88807b296428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153
>  #1: ffff88805bdba7e8 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188
> 2 locks held by syz.8.28/6265:
>  #0: ffff88807b296428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36
>  #1: ffff88805bdba7e8 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline]
>  #1: ffff88805bdba7e8 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65
> 2 locks held by syz.9.29/6301:
>  #0: ffff88805912a428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153
>  #1: ffff88805f8c1498 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188
> 2 locks held by syz.9.29/6302:
>  #0: ffff88805912a428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36
>  #1: ffff88805f8c1498 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline]
>  #1: ffff88805f8c1498 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65
>
> =============================================
>
> NMI backtrace for cpu 0
> CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
> Call Trace:
>  <TASK>
>  __dump_stack lib/dump_stack.c:94 [inline]
>  dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
>  nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
>  nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
>  trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
>  check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline]
>  watchdog+0xf0e/0x1260 kernel/hung_task.c:491
>  kthread+0x3c2/0x780 kernel/kthread.c:463
>  ret_from_fork+0x56a/0x730 arch/x86/kernel/process.c:148
>  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
>  </TASK>
> Sending NMI from CPU 0 to CPUs 1:
> NMI backtrace for cpu 1
> CPU: 1 UID: 0 PID: 49 Comm: kworker/u8:3 Not tainted syzkaller #0 PREEMPT(full)
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
> Workqueue: bat_events batadv_nc_worker
> RIP: 0010:iterate_chain_key kernel/locking/lockdep.c:451 [inline]
> RIP: 0010:__lock_acquire+0x642/0x1ce0 kernel/locking/lockdep.c:5225
> Code: 08 45 85 d2 0f 85 6f 04 00 00 4c 89 e7 89 4c 24 08 e8 92 ac ff ff 8b 4c 24 08 48 83 78 40 00 0f 84 c2 0a 00 00 0f b7 44 24 10 <8b> 7c 24 28 44 8b 74 24 20 c1 e0 0d 66 0b 04 24 98 29 f8 8b 7c 24
> RSP: 0018:ffffc90000b97958 EFLAGS: 00000086
> RAX: 0000000000000700 RBX: ffff888022ae2f30 RCX: 00000000748bd351
> RDX: 0000000000000000 RSI: ffff888022ae2f80 RDI: ffff888022ae2f80
> RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
> R10: 0000000000000002 R11: 0000000000000000 R12: ffff888022ae2f80
> R13: ffff888022ae2440 R14: 0000000000000002 R15: 0000000000000003
> FS:  0000000000000000(0000) GS:ffff8881247b2000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 000055fb93cf9be0 CR3: 000000000e380000 CR4: 00000000003526f0
> Call Trace:
>  <TASK>
>  lock_acquire kernel/locking/lockdep.c:5868 [inline]
>  lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825
>  __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
>  _raw_spin_lock_bh+0x33/0x40 kernel/locking/spinlock.c:178
>  spin_lock_bh include/linux/spinlock.h:356 [inline]
>  batadv_nc_purge_paths+0xd9/0x3a0 net/batman-adv/network-coding.c:442
>  batadv_nc_worker+0x958/0x1030 net/batman-adv/network-coding.c:722
>  process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3236
>  process_scheduled_works kernel/workqueue.c:3319 [inline]
>  worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
>  kthread+0x3c2/0x780 kernel/kthread.c:463
>  ret_from_fork+0x56a/0x730 arch/x86/kernel/process.c:148
>  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
>  </TASK>
>
>
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@googlegroups.com.
>
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
>
> If the report is already addressed, let syzbot know by replying with:
> #syz fix: exact-commit-title
>
> If you want syzbot to run the reproducer, reply with:
> #syz test: git://repo/address.git branch-or-commit-hash
> If you attach or paste a git patch, syzbot will apply it before testing.
>
> If you want to overwrite report's subsystems, reply with:
> #syz set subsystems: new-subsystem
> (See the list of subsystem names on the web dashboard)
>
> If the report is a duplicate of another one, reply with:
> #syz dup: exact-subject-of-another-report
>
> If you want to undo deduplication, reply with:
> #syz undup


^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [syzbot] [netfs?] INFO: task hung in vfs_utimes (3)
  2025-09-19  0:47 ` syzbot
  2025-09-19  2:18   ` Hillf Danton
@ 2025-09-19  7:14   ` Oleg Nesterov
  1 sibling, 0 replies; 10+ messages in thread
From: Oleg Nesterov @ 2025-09-19  7:14 UTC (permalink / raw)
  To: syzbot
  Cc: brauner, dhowells, jack, jlayton, linux-fsdevel, linux-kernel,
	netfs, pc, syzkaller-bugs, viro

On 09/18, syzbot wrote:
>
> syzbot has bisected this issue to:
>
> commit aaec5a95d59615523db03dd53c2052f0a87beea7
> Author: Oleg Nesterov <oleg@redhat.com>
> Date:   Thu Jan 2 14:07:15 2025 +0000
>
>     pipe_read: don't wake up the writer if the pipe is still full
>
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=175fa534580000
> start commit:   46a51f4f5eda Merge tag 'for-v6.17-rc' of git://git.kernel...
> git tree:       upstream
> final oops:     https://syzkaller.appspot.com/x/report.txt?x=14dfa534580000
> console output: https://syzkaller.appspot.com/x/log.txt?x=10dfa534580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=8f01d8629880e620
> dashboard link: https://syzkaller.appspot.com/bug?extid=3815dce0acab6c55984e
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17692f62580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1361f47c580000
>
> Reported-by: syzbot+3815dce0acab6c55984e@syzkaller.appspotmail.com
> Fixes: aaec5a95d596 ("pipe_read: don't wake up the writer if the pipe is still full")

#syz dup: [syzbot] [fs?] [mm?] INFO: task hung in v9fs_file_fsync

https://lore.kernel.org/all/68a2de8f.050a0220.e29e5.0097.GAE@google.com/


^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [syzbot] [netfs?] INFO: task hung in vfs_utimes (3)
  2025-09-19  6:48 ` Oleg Nesterov
@ 2025-09-19 12:22   ` Hillf Danton
  2025-09-19 13:25   ` Dominique Martinet
  1 sibling, 0 replies; 10+ messages in thread
From: Hillf Danton @ 2025-09-19 12:22 UTC (permalink / raw)
  To: Oleg Nesterov
  Cc: syzbot, Dominique Martinet, dhowells, linux-fsdevel, linux-kernel,
	netfs, pc, syzkaller-bugs

On Fri, 19 Sep 2025 08:48:00 +0200 Oleg Nesterov wrote:
> Dominique,
> 
> according to
> 
> 	https://lore.kernel.org/all/20250919021852.7157-1-hdanton@sina.com/
> 	https://lore.kernel.org/all/68ccc372.050a0220.28a605.0016.GAE@google.com/
> 
> this is yet another issue seems to be fixed by
> 
> 	[PATCH] 9p/trans_fd: p9_fd_request: kick rx thread if EPOLLIN
> 	https://lore.kernel.org/all/20250819161013.GB11345@redhat.com/
> 
> are you going to apply it?
> 
> Hillf, thanks a lot!
> 
Happy to test your fix.

Hillf Danton

> Oleg.

^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [syzbot] [netfs?] INFO: task hung in vfs_utimes (3)
  2025-09-19  6:48 ` Oleg Nesterov
  2025-09-19 12:22   ` Hillf Danton
@ 2025-09-19 13:25   ` Dominique Martinet
  1 sibling, 0 replies; 10+ messages in thread
From: Dominique Martinet @ 2025-09-19 13:25 UTC (permalink / raw)
  To: Oleg Nesterov
  Cc: syzbot, Hillf Danton, dhowells, linux-fsdevel, linux-kernel,
	netfs, pc, syzkaller-bugs

Hi Oleg,

Oleg Nesterov wrote on Fri, Sep 19, 2025 at 08:48:00AM +0200:
> this is yet another issue seems to be fixed by
> 
> 	[PATCH] 9p/trans_fd: p9_fd_request: kick rx thread if EPOLLIN
> 	https://lore.kernel.org/all/20250819161013.GB11345@redhat.com/
> 
> are you going to apply it?

Sorry for the lack of reply, I had meant to deal with it earlier but
other patches came in and it fell into the cracks.

I've just pushed your patch to my -next branch, I'll submit it to Linus
during the merge window in a couple of weeks

-- 
Dominique Martinet | Asmadeus

^ permalink raw reply	[flat|nested] 10+ messages in thread

end of thread, other threads:[~2025-09-19 13:26 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-09-17 22:54 [syzbot] [netfs?] INFO: task hung in vfs_utimes (3) syzbot
2025-09-19  0:47 ` syzbot
2025-09-19  2:18   ` Hillf Danton
2025-09-19  2:44     ` syzbot
2025-09-19  7:14   ` Oleg Nesterov
2025-09-19  1:29 ` Forwarded: " syzbot
2025-09-19  6:48 ` Oleg Nesterov
2025-09-19 12:22   ` Hillf Danton
2025-09-19 13:25   ` Dominique Martinet
     [not found] <20250919012918.213435-1-lizhi.xu@windriver.com>
2025-09-19  2:04 ` syzbot

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