[syzbot] [ext4?] INFO: task hung in ext4_load_tail_bh

[syzbot <syzbot+479d1ce6391270ec5dc6@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    ff4c5a0de1f2 arm64/mm: Optimize TLB flush in unmap_hotplug..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=148c611e580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=ecdef466b08b9772
dashboard link: https://syzkaller.appspot.com/bug?extid=479d1ce6391270ec5dc6
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
userspace arch: arm64
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12eb1e89580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12adbe89580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/0ea05371791a/disk-ff4c5a0d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/968513dc8b51/vmlinux-ff4c5a0d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a1a240044ae4/Image-ff4c5a0d.gz.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/7d8146d523b0/mount_0.gz
  fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=13bac289580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+479d1ce6391270ec5dc6@syzkaller.appspotmail.com

INFO: task syz.5.7528:29358 blocked in I/O wait for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.7528      state:D stack:0     pid:29358 tgid:29355 ppid:27464  task_flags:0x400140 flags:0x00000011
Call trace:
 __switch_to+0x2b0/0x6e0 arch/arm64/kernel/process.c:775 (T)
 context_switch kernel/sched/core.c:5510 [inline]
 __schedule+0x1370/0x2d80 kernel/sched/core.c:7234
 __schedule_loop kernel/sched/core.c:7311 [inline]
 schedule+0x13c/0x20c kernel/sched/core.c:7326
 io_schedule+0x1c/0xe0 kernel/sched/core.c:8154
 folio_wait_bit_common+0x6b8/0xa30 mm/filemap.c:1323
 __folio_lock mm/filemap.c:1704 [inline]
 folio_lock include/linux/pagemap.h:1157 [inline]
 __filemap_get_folio_mpol+0x1f4/0x1054 mm/filemap.c:1960
 __filemap_get_folio include/linux/pagemap.h:761 [inline]
 ext4_load_tail_bh+0x94/0x704 fs/ext4/inode.c:4040
 ext4_block_do_zero_range fs/ext4/inode.c:4111 [inline]
 ext4_block_zero_range+0xd8/0x7b0 fs/ext4/inode.c:4199
 ext4_block_zero_eof+0x22c/0x4b8 fs/ext4/inode.c:4229
 ext4_truncate+0x500/0x10d4 fs/ext4/inode.c:4632
 ext4_truncate_failed_write fs/ext4/truncate.h:22 [inline]
 ext4_write_end+0x598/0x9e0 fs/ext4/inode.c:1495
 generic_perform_write+0x504/0x7a4 mm/filemap.c:4379
 ext4_buffered_write_iter+0xd0/0x2ec fs/ext4/file.c:316
 ext4_file_write_iter+0x1dc/0x134c fs/ext4/file.c:-1
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x51c/0xa0c fs/read_write.c:687
 ksys_write+0x12c/0x228 fs/read_write.c:739
 __do_sys_write fs/read_write.c:750 [inline]
 __se_sys_write fs/read_write.c:747 [inline]
 __arm64_sys_write+0x7c/0x90 fs/read_write.c:747
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121
 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140
 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:736
 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:755
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594
INFO: task syz.5.7528:29366 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.7528      state:D stack:0     pid:29366 tgid:29355 ppid:27464  task_flags:0x440040 flags:0x00000011
Call trace:
 __switch_to+0x2b0/0x6e0 arch/arm64/kernel/process.c:775 (T)
 context_switch kernel/sched/core.c:5510 [inline]
 __schedule+0x1370/0x2d80 kernel/sched/core.c:7234
 __schedule_loop kernel/sched/core.c:7311 [inline]
 schedule+0x13c/0x20c kernel/sched/core.c:7326
 schedule_preempt_disabled+0x18/0x2c kernel/sched/core.c:7383
 rwsem_down_read_slowpath+0x530/0x7b0 kernel/locking/rwsem.c:1114
 __down_read_common kernel/locking/rwsem.c:1291 [inline]
 __down_read kernel/locking/rwsem.c:1304 [inline]
 down_read+0xa0/0x2bc kernel/locking/rwsem.c:1576
 filemap_invalidate_lock_shared include/linux/fs.h:1089 [inline]
 page_cache_ra_order+0x334/0xe20 mm/readahead.c:517
 page_cache_sync_ra+0x66c/0xaf0 mm/readahead.c:649
 page_cache_sync_readahead include/linux/pagemap.h:1395 [inline]
 collapse_file mm/khugepaged.c:2335 [inline]
 collapse_scan_file+0x16fc/0x4834 mm/khugepaged.c:2773
 collapse_single_pmd+0x3c0/0x3b78 mm/khugepaged.c:2808
 madvise_collapse+0x2a4/0x728 mm/khugepaged.c:3234
 madvise_vma_behavior+0x408/0x3390 mm/madvise.c:1364
 madvise_walk_vmas+0x4c8/0x9bc mm/madvise.c:1713
 madvise_do_behavior+0x5f0/0x7c0 mm/madvise.c:1908
 do_madvise+0x28c/0x2f0 mm/madvise.c:2006
 __do_sys_madvise mm/madvise.c:2015 [inline]
 __se_sys_madvise mm/madvise.c:2013 [inline]
 __arm64_sys_madvise+0xa4/0xc0 mm/madvise.c:2013
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121
 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140
 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:736
 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:755
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594

Showing all locks held in the system:
2 locks held by kworker/u8:0/12:
1 lock held by khungtaskd/31:
 #0: ffff800088cb6f20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #0: ffff800088cb6f20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
 #0: ffff800088cb6f20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x4c/0x188 kernel/locking/lockdep.c:6775
1 lock held by pr/ttyAMA-1/41:
2 locks held by getty/4492:
 #0: ffff0000d159a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
 #1: ffff80009248b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x348/0xf78 drivers/tty/n_tty.c:2211
3 locks held by udevd/4753:
2 locks held by kworker/0:4/4834:
3 locks held by udevd/5195:
1 lock held by udevd/5459:
2 locks held by udevd/25825:
4 locks held by syz.5.7528/29358:
 #0: ffff0000cd7f3b30 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x100/0x144 fs/file.c:1259
 #1: ffff0000d54a2450 (sb_writers#3){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2728 [inline]
 #1: ffff0000d54a2450 (sb_writers#3){.+.+}-{0:0}, at: vfs_write+0x248/0xa0c fs/read_write.c:683
 #2: ffff0000dfbf9fa0 (&sb->s_type->i_mutex_key#10){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
 #2: ffff0000dfbf9fa0 (&sb->s_type->i_mutex_key#10){++++}-{4:4}, at: ext4_buffered_write_iter+0xa0/0x2ec fs/ext4/file.c:311
 #3: ffff0000dfbfa138 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock include/linux/fs.h:1079 [inline]
 #3: ffff0000dfbfa138 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_truncate_failed_write fs/ext4/truncate.h:20 [inline]
 #3: ffff0000dfbfa138 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_write_end+0x574/0x9e0 fs/ext4/inode.c:1495
1 lock held by syz.5.7528/29366:
 #0: ffff0000dfbfa138 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:1089 [inline]
 #0: ffff0000dfbfa138 (mapping.invalidate_lock#2){++++}-{4:4}, at: page_cache_ra_order+0x334/0xe20 mm/readahead.c:517
4 locks held by syz.3.8462/32291:
 #0: ffff0000d18440f0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x100/0x144 fs/file.c:1259
 #1: ffff0000ed44a450 (sb_writers#3){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2728 [inline]
 #1: ffff0000ed44a450 (sb_writers#3){.+.+}-{0:0}, at: vfs_write+0x248/0xa0c fs/read_write.c:683
 #2: ffff0000efc86aa0 (&sb->s_type->i_mutex_key#10){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
 #2: ffff0000efc86aa0 (&sb->s_type->i_mutex_key#10){++++}-{4:4}, at: ext4_buffered_write_iter+0xa0/0x2ec fs/ext4/file.c:311
 #3: ffff0000efc86c38 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock include/linux/fs.h:1079 [inline]
 #3: ffff0000efc86c38 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_truncate_failed_write fs/ext4/truncate.h:20 [inline]
 #3: ffff0000efc86c38 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_write_end+0x574/0x9e0 fs/ext4/inode.c:1495
1 lock held by syz.3.8462/32302:
 #0: ffff0000efc86c38 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:1089 [inline]
 #0: ffff0000efc86c38 (mapping.invalidate_lock#2){++++}-{4:4}, at: page_cache_ra_order+0x334/0xe20 mm/readahead.c:517
4 locks held by syz.7.12097/10967:
 #0: ffff0000c98c2630 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x100/0x144 fs/file.c:1259
 #1: ffff0000d4d4c450 (sb_writers#3){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2728 [inline]
 #1: ffff0000d4d4c450 (sb_writers#3){.+.+}-{0:0}, at: vfs_write+0x248/0xa0c fs/read_write.c:683
 #2: ffff0000dfba1fa0 (&sb->s_type->i_mutex_key#10){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
 #2: ffff0000dfba1fa0 (&sb->s_type->i_mutex_key#10){++++}-{4:4}, at: ext4_buffered_write_iter+0xa0/0x2ec fs/ext4/file.c:311
 #3: ffff0000dfba2138 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock include/linux/fs.h:1079 [inline]
 #3: ffff0000dfba2138 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_truncate_failed_write fs/ext4/truncate.h:20 [inline]
 #3: ffff0000dfba2138 (mapping.invalidate_lock#2){++++}-{4:4}, at: ext4_write_end+0x574/0x9e0 fs/ext4/inode.c:1495
1 lock held by syz.7.12097/10978:
 #0: ffff0000dfba2138 (mapping.invalidate_lock#2){++++}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:1089 [inline]
 #0: ffff0000dfba2138 (mapping.invalidate_lock#2){++++}-{4:4}, at: page_cache_ra_order+0x334/0xe20 mm/readahead.c:517
1 lock held by syz-executor/12531:
1 lock held by syz.2.13521/15260:
1 lock held by syz.1.13518/15265:

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---
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