From: syzbot <syzbot+aa7397130ec6a8c2e2d9@syzkaller.appspotmail.com>
To: jack@suse.com, jfs-discussion@lists.sourceforge.net,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
reiserfs-devel@vger.kernel.org, shaggy@kernel.org,
syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [reiserfs?] INFO: task hung in deactivate_super (2)
Date: Thu, 04 Jan 2024 03:28:28 -0800 [thread overview]
Message-ID: <000000000000d06740060e1d074d@google.com> (raw)
In-Reply-To: <00000000000082de1c05f81467ed@google.com>
syzbot has found a reproducer for the following issue on:
HEAD commit: ac865f00af29 Merge tag 'pci-v6.7-fixes-2' of git://git.ker..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=11f14c55e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=655f8abe9fe69b3b
dashboard link: https://syzkaller.appspot.com/bug?extid=aa7397130ec6a8c2e2d9
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1669644de80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=137d7db5e80000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9a1f24b8b8e9/disk-ac865f00.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b09904d69477/vmlinux-ac865f00.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8130ed70d938/bzImage-ac865f00.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/ea2e844115b1/mount_1.gz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+aa7397130ec6a8c2e2d9@syzkaller.appspotmail.com
INFO: task syz-executor393:5056 blocked for more than 143 seconds.
Not tainted 6.7.0-rc8-syzkaller-00024-gac865f00af29 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor393 state:D stack:25016 pid:5056 tgid:5056 ppid:5055 flags:0x00004002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5376 [inline]
__schedule+0x1961/0x4ab0 kernel/sched/core.c:6688
__schedule_loop kernel/sched/core.c:6763 [inline]
schedule+0x149/0x260 kernel/sched/core.c:6778
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6835
rwsem_down_write_slowpath+0xeea/0x13b0 kernel/locking/rwsem.c:1178
__down_write_common+0x1aa/0x200 kernel/locking/rwsem.c:1306
__super_lock fs/super.c:56 [inline]
__super_lock_excl fs/super.c:71 [inline]
deactivate_super+0xad/0xf0 fs/super.c:516
cleanup_mnt+0x426/0x4c0 fs/namespace.c:1256
task_work_run+0x24a/0x300 kernel/task_work.c:180
ptrace_notify+0x2cd/0x380 kernel/signal.c:2399
ptrace_report_syscall include/linux/ptrace.h:411 [inline]
ptrace_report_syscall_exit include/linux/ptrace.h:473 [inline]
syscall_exit_work kernel/entry/common.c:251 [inline]
syscall_exit_to_user_mode_prepare kernel/entry/common.c:278 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
syscall_exit_to_user_mode+0x168/0x2a0 kernel/entry/common.c:296
do_syscall_64+0x52/0x110 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7f4ae237a577
RSP: 002b:00007fffedd426b8 EFLAGS: 00000206 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 000000000000daf5 RCX: 00007f4ae237a577
RDX: 0000000000000000 RSI: 000000000000000a RDI: 00007fffedd42770
RBP: 00007fffedd42770 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000206 R12: 00007fffedd437e0
R13: 000055555600b6c0 R14: 431bde82d7b634db R15: 00007fffedd43800
</TASK>
INFO: task syz-executor393:5082 blocked for more than 143 seconds.
Not tainted 6.7.0-rc8-syzkaller-00024-gac865f00af29 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor393 state:D stack:27056 pid:5082 tgid:5082 ppid:5059 flags:0x00004006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5376 [inline]
__schedule+0x1961/0x4ab0 kernel/sched/core.c:6688
__schedule_loop kernel/sched/core.c:6763 [inline]
schedule+0x149/0x260 kernel/sched/core.c:6778
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6835
rwsem_down_read_slowpath kernel/locking/rwsem.c:1086 [inline]
__down_read_common kernel/locking/rwsem.c:1250 [inline]
__down_read kernel/locking/rwsem.c:1263 [inline]
down_read+0x703/0xa40 kernel/locking/rwsem.c:1528
__super_lock fs/super.c:58 [inline]
super_lock+0x176/0x3a0 fs/super.c:117
super_lock_shared fs/super.c:146 [inline]
iterate_supers+0x8c/0x180 fs/super.c:969
quota_sync_all fs/quota/quota.c:69 [inline]
__do_sys_quotactl fs/quota/quota.c:938 [inline]
__se_sys_quotactl+0x391/0xa30 fs/quota/quota.c:917
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x45/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7f4ae2379319
RSP: 002b:00007fffedd437a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f4ae2379319
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff80000100
RBP: 0000000000000000 R08: 0000000000000000 R09: 00007fffedd437e0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffedd437cc
R13: 0000000000000001 R14: 431bde82d7b634db R15: 00007fffedd43800
</TASK>
INFO: task syz-executor393:5083 blocked for more than 143 seconds.
Not tainted 6.7.0-rc8-syzkaller-00024-gac865f00af29 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor393 state:D stack:26736 pid:5083 tgid:5083 ppid:5060 flags:0x00004006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5376 [inline]
__schedule+0x1961/0x4ab0 kernel/sched/core.c:6688
__schedule_loop kernel/sched/core.c:6763 [inline]
schedule+0x149/0x260 kernel/sched/core.c:6778
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6835
rwsem_down_read_slowpath kernel/locking/rwsem.c:1086 [inline]
__down_read_common kernel/locking/rwsem.c:1250 [inline]
__down_read kernel/locking/rwsem.c:1263 [inline]
down_read+0x703/0xa40 kernel/locking/rwsem.c:1528
__super_lock fs/super.c:58 [inline]
super_lock+0x176/0x3a0 fs/super.c:117
super_lock_shared fs/super.c:146 [inline]
iterate_supers+0x8c/0x180 fs/super.c:969
quota_sync_all fs/quota/quota.c:69 [inline]
__do_sys_quotactl fs/quota/quota.c:938 [inline]
__se_sys_quotactl+0x391/0xa30 fs/quota/quota.c:917
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x45/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7f4ae2379319
RSP: 002b:00007fffedd437a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f4ae2379319
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff80000100
RBP: 0000000000000000 R08: 0000000000000000 R09: 00007fffedd437e0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffedd437cc
R13: 0000000000000001 R14: 431bde82d7b634db R15: 00007fffedd43800
</TASK>
INFO: task syz-executor393:5084 blocked for more than 144 seconds.
Not tainted 6.7.0-rc8-syzkaller-00024-gac865f00af29 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor393 state:D stack:27056 pid:5084 tgid:5084 ppid:5061 flags:0x00004006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5376 [inline]
__schedule+0x1961/0x4ab0 kernel/sched/core.c:6688
__schedule_loop kernel/sched/core.c:6763 [inline]
schedule+0x149/0x260 kernel/sched/core.c:6778
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6835
rwsem_down_read_slowpath kernel/locking/rwsem.c:1086 [inline]
__down_read_common kernel/locking/rwsem.c:1250 [inline]
__down_read kernel/locking/rwsem.c:1263 [inline]
down_read+0x703/0xa40 kernel/locking/rwsem.c:1528
__super_lock fs/super.c:58 [inline]
super_lock+0x176/0x3a0 fs/super.c:117
super_lock_shared fs/super.c:146 [inline]
iterate_supers+0x8c/0x180 fs/super.c:969
quota_sync_all fs/quota/quota.c:69 [inline]
__do_sys_quotactl fs/quota/quota.c:938 [inline]
__se_sys_quotactl+0x391/0xa30 fs/quota/quota.c:917
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x45/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7f4ae2379319
RSP: 002b:00007fffedd437a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f4ae2379319
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff80000100
RBP: 0000000000000000 R08: 0000000000000000 R09: 00007fffedd437e0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffedd437cc
R13: 0000000000000001 R14: 431bde82d7b634db R15: 00007fffedd43800
</TASK>
Showing all locks held in the system:
1 lock held by khungtaskd/29:
#0: ffffffff8d92dae0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:301 [inline]
#0: ffffffff8d92dae0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:747 [inline]
#0: ffffffff8d92dae0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6614
2 locks held by getty/4808:
#0: ffff88802667c0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90002f062f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6b4/0x1e10 drivers/tty/n_tty.c:2201
1 lock held by syz-executor393/5056:
#0: ffff888029d1e0e0 (&type->s_umount_key#24){++++}-{3:3}, at: __super_lock fs/super.c:56 [inline]
#0: ffff888029d1e0e0 (&type->s_umount_key#24){++++}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline]
#0: ffff888029d1e0e0 (&type->s_umount_key#24){++++}-{3:3}, at: deactivate_super+0xad/0xf0 fs/super.c:516
4 locks held by syz-executor393/5078:
#0: ffff888029d1e0e0 (&type->s_umount_key#24){++++}-{3:3}, at: __super_lock fs/super.c:58 [inline]
#0: ffff888029d1e0e0 (&type->s_umount_key#24){++++}-{3:3}, at: super_lock+0x176/0x3a0 fs/super.c:117
#1: ffffc90003b890f0 (&journal->j_mutex){+.+.}-{3:3}, at: reiserfs_mutex_lock_safe fs/reiserfs/reiserfs.h:813 [inline]
#1: ffffc90003b890f0 (&journal->j_mutex){+.+.}-{3:3}, at: lock_journal fs/reiserfs/journal.c:533 [inline]
#1: ffffc90003b890f0 (&journal->j_mutex){+.+.}-{3:3}, at: do_journal_begin_r+0x352/0x1030 fs/reiserfs/journal.c:3047
#2: ffff8880b993c358 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:558
#3: ffff8880b993c358 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:558
2 locks held by syz-executor393/5079:
#0: ffff888029d1e0e0 (&type->s_umount_key#24){++++}-{3:3}, at: __super_lock fs/super.c:58 [inline]
#0: ffff888029d1e0e0 (&type->s_umount_key#24){++++}-{3:3}, at: super_lock+0x176/0x3a0 fs/super.c:117
#1: ffffc90003b890f0 (&journal->j_mutex){+.+.}-{3:3}, at: reiserfs_mutex_lock_safe fs/reiserfs/reiserfs.h:813 [inline]
#1: ffffc90003b890f0 (&journal->j_mutex){+.+.}-{3:3}, at: lock_journal fs/reiserfs/journal.c:533 [inline]
#1: ffffc90003b890f0 (&journal->j_mutex){+.+.}-{3:3}, at: do_journal_begin_r+0x352/0x1030 fs/reiserfs/journal.c:3047
1 lock held by syz-executor393/5082:
#0: ffff888029d1e0e0 (&type->s_umount_key#24){++++}-{3:3}, at: __super_lock fs/super.c:58 [inline]
#0: ffff888029d1e0e0 (&type->s_umount_key#24){++++}-{3:3}, at: super_lock+0x176/0x3a0 fs/super.c:117
1 lock held by syz-executor393/5083:
#0: ffff888029d1e0e0 (&type->s_umount_key#24){++++}-{3:3}, at: __super_lock fs/super.c:58 [inline]
#0: ffff888029d1e0e0 (&type->s_umount_key#24){++++}-{3:3}, at: super_lock+0x176/0x3a0 fs/super.c:117
1 lock held by syz-executor393/5084:
#0: ffff888029d1e0e0 (&type->s_umount_key#24){++++}-{3:3}, at: __super_lock fs/super.c:58 [inline]
#0: ffff888029d1e0e0 (&type->s_umount_key#24){++++}-{3:3}, at: super_lock+0x176/0x3a0 fs/super.c:117
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 29 Comm: khungtaskd Not tainted 6.7.0-rc8-syzkaller-00024-gac865f00af29 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
nmi_cpu_backtrace+0x498/0x4d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x198/0x310 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
watchdog+0xfaf/0xff0 kernel/hung_task.c:379
kthread+0x2d3/0x370 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242
</TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 5078 Comm: syz-executor393 Not tainted 6.7.0-rc8-syzkaller-00024-gac865f00af29 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
RIP: 0010:kasan_check_range+0x7/0x290 mm/kasan/generic.c:186
Code: 84 47 ff ff ff 48 ff c8 48 39 d8 0f 84 3b ff ff ff 48 89 df 48 c7 c6 02 91 12 8d e8 83 0a e7 ff 90 0f 0b 66 0f 1f 00 55 41 57 <41> 56 41 54 53 b0 01 48 85 f6 0f 84 a0 01 00 00 4c 8d 04 37 49 39
RSP: 0018:ffffc90003a5e838 EFLAGS: 00000046
RAX: 0000000000000002 RBX: 00000000000000a5 RCX: ffffffff816d37ac
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff90dd9370
RBP: ffff88802451c780 R08: ffffffff90dd9377 R09: 1ffffffff21bb26e
R10: dffffc0000000000 R11: fffffbfff21bb26f R12: 0000000000000001
R13: ffff88802451bb80 R14: 1ffff110048a38f4 R15: ffff88802451c7a0
FS: 000055555600a380(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f934ceb7580 CR3: 0000000023d95000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<NMI>
</NMI>
<TASK>
instrument_atomic_read include/linux/instrumented.h:68 [inline]
_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
__lock_acquire+0xc5c/0x1fd0 kernel/locking/lockdep.c:5107
lock_acquire+0x1e3/0x530 kernel/locking/lockdep.c:5754
do_write_seqcount_begin_nested include/linux/seqlock.h:525 [inline]
do_write_seqcount_begin include/linux/seqlock.h:551 [inline]
psi_group_change+0x113/0x12d0 kernel/sched/psi.c:787
psi_task_change+0xfd/0x280 kernel/sched/psi.c:912
psi_enqueue kernel/sched/stats.h:139 [inline]
enqueue_task+0x29c/0x2f0 kernel/sched/core.c:2091
activate_task kernel/sched/core.c:2125 [inline]
ttwu_do_activate+0x1d7/0x760 kernel/sched/core.c:3770
ttwu_queue kernel/sched/core.c:4021 [inline]
try_to_wake_up+0x86d/0x1440 kernel/sched/core.c:4342
kick_pool+0x2f4/0x3d0 kernel/workqueue.c:1142
__queue_work+0xbfc/0x1000 kernel/workqueue.c:1797
mod_delayed_work_on+0x105/0x250 kernel/workqueue.c:2021
kblockd_mod_delayed_work_on+0x29/0x40 block/blk-core.c:1046
blk_insert_flush+0x3cb/0x4e0 block/blk-flush.c:456
blk_mq_submit_bio+0xff6/0x2140 block/blk-mq.c:3004
__submit_bio+0x239/0x2e0 block/blk-core.c:607
__submit_bio_noacct_mq block/blk-core.c:686 [inline]
submit_bio_noacct_nocheck+0x91d/0xc70 block/blk-core.c:715
submit_bh fs/buffer.c:2826 [inline]
__sync_dirty_buffer+0x23b/0x390 fs/buffer.c:2864
_update_journal_header_block+0x401/0x540 fs/reiserfs/journal.c:1270
update_journal_header_block fs/reiserfs/journal.c:1289 [inline]
flush_journal_list+0x106f/0x1c80 fs/reiserfs/journal.c:1589
flush_used_journal_lists+0x1256/0x15d0 fs/reiserfs/journal.c:1828
do_journal_end+0x3d51/0x4b40
do_journal_begin_r+0x970/0x1030
journal_begin+0x14c/0x360 fs/reiserfs/journal.c:3254
reiserfs_sync_fs+0xb0/0x150 fs/reiserfs/super.c:77
dquot_quota_sync+0xdb/0x490 fs/quota/dquot.c:753
iterate_supers+0xc2/0x180 fs/super.c:971
quota_sync_all fs/quota/quota.c:69 [inline]
__do_sys_quotactl fs/quota/quota.c:938 [inline]
__se_sys_quotactl+0x391/0xa30 fs/quota/quota.c:917
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x45/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7f4ae2379319
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 21 18 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fffedd437a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f4ae2379319
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff80000100
RBP: 0000000000000000 R08: 0000000000000000 R09: 00007fffedd437e0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffedd437cc
R13: 0000000000000001 R14: 431bde82d7b634db R15: 00007fffedd43800
</TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 2.090 msecs
---
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.
next parent reply other threads:[~2024-01-04 11:28 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <00000000000082de1c05f81467ed@google.com>
2024-01-04 11:28 ` syzbot [this message]
2024-04-02 12:53 ` [syzbot] [reiserfs?] INFO: task hung in deactivate_super (2) syzbot
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=000000000000d06740060e1d074d@google.com \
--to=syzbot+aa7397130ec6a8c2e2d9@syzkaller.appspotmail.com \
--cc=jack@suse.com \
--cc=jfs-discussion@lists.sourceforge.net \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=reiserfs-devel@vger.kernel.org \
--cc=shaggy@kernel.org \
--cc=syzkaller-bugs@googlegroups.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).