CVE-2026-53284

In the Linux kernel, the following vulnerability has been resolved:

btrfs: only release the dirty pages io tree after successful writes

[WARNING]
With extra warning on dirty extent buffers at umount (aka, the next
patch in the series), test case generic/388 can trigger the following
warning about dirty extent buffers at unmount time:

  BTRFS critical (device dm-2 state E): emergency shutdown
  BTRFS error (device dm-2 state E): error while writing out transaction: -30
  BTRFS warning (device dm-2 state E): Skipping commit of aborted transaction.
  BTRFS error (device dm-2 state EA): Transaction 9 aborted (error -30)
  BTRFS: error (device dm-2 state EA) in cleanup_transaction:2068: errno=-30 Readonly filesystem
  BTRFS info (device dm-2 state EA): forced readonly
  BTRFS info (device dm-2 state EA): last unmount of filesystem 4fbf2e15-f941-49a0-bc7c-716315d2777c
  ------------[ cut here ]------------
  WARNING: disk-io.c:3311 at invalidate_and_check_btree_folios+0xfd/0x1ca [btrfs], CPU#8: umount/914368
  CPU: 8 UID: 0 PID: 914368 Comm: umount Tainted: G           OE       7.1.0-rc1-custom+ #372 PREEMPT(full)  2de38db8d1deae71fde295430a0ff3ab98ccf596
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS unknown 02/02/2022
  RIP: 0010:invalidate_and_check_btree_folios+0xfd/0x1ca [btrfs]
  Call Trace:
   <TASK>
   close_ctree+0x52e/0x574 [btrfs d2f0b1cd330d1287e7a9919d112eadfc0e914efd]
   generic_shutdown_super+0x89/0x1a0
   kill_anon_super+0x16/0x40
   btrfs_kill_super+0x16/0x20 [btrfs d2f0b1cd330d1287e7a9919d112eadfc0e914efd]
   deactivate_locked_super+0x2d/0xb0
   cleanup_mnt+0xdc/0x140
   task_work_run+0x5a/0xa0
   exit_to_user_mode_loop+0x123/0x4b0
   do_syscall_64+0x243/0x7c0
   entry_SYSCALL_64_after_hwframe+0x4b/0x53
   </TASK>
  ---[ end trace 0000000000000000 ]---
  BTRFS warning (device dm-2 state EA): unable to release extent buffer 30539776 owner 9 gen 9 refs 2 flags 0x7
  BTRFS warning (device dm-2 state EA): unable to release extent buffer 30621696 owner 257 gen 9 refs 2 flags 0x7
  BTRFS warning (device dm-2 state EA): unable to release extent buffer 30638080 owner 258 gen 9 refs 2 flags 0x7
  BTRFS warning (device dm-2 state EA): unable to release extent buffer 30654464 owner 7 gen 9 refs 2 flags 0x7
  BTRFS warning (device dm-2 state EA): unable to release extent buffer 30703616 owner 2 gen 9 refs 2 flags 0x7
  BTRFS warning (device dm-2 state EA): unable to release extent buffer 30720000 owner 10 gen 9 refs 2 flags 0x7
  BTRFS warning (device dm-2 state EA): unable to release extent buffer 30736384 owner 4 gen 9 refs 2 flags 0x7
  BTRFS warning (device dm-2 state EA): unable to release extent buffer 30752768 owner 11 gen 9 refs 2 flags 0x7

I'm using a stripped down version, which seems to trigger the warning
more reliably:

  _fsstress_pid=""
  workload()
  {
  	dmesg -C
  	mkfs.btrfs -f -K $dev > /dev/null
  	echo 1 > /sys/kernel/debug/clear_warn_once
  	mount $dev $mnt
  	$fsstress -w -n 1024 -p 4 -d $mnt &
  	_fsstress_pid=$!
  	sleep 0
  	$godown $mnt
  	pkill --echo -PIPE fsstress > /dev/null
  	wait $_fsstress_pid
  	unset _fsstress_pid
  	umount $mnt

  	if dmesg | grep -q "WARNING"; then
  		fail
  	fi
  }

  for (( i = 0; i < $runtime; i++ )); do
  	echo "=== $i/$runtime ==="
  	workload
  done

[CAUSE]
Inside btrfs_write_and_wait_transaction(), we first try to write all
dirty ebs, then wait for them to finish.

After that we call btrfs_extent_io_tree_release() to free all
extent states from dirty_pages io tree.

However if we hit an error from btrfs_write_marked_extent(), then we
still call btrfs_extent_io_tree_release() to clear that dirty_pages io
tree, which may contain dirty records that we haven't yet submitted.

Furthermore, the later transaction cleanup path will utilize that
dirty_pages io tree to properly cleanup those dirty ebs, but since it's
already empty, no dirty ebs are properly cleaned up, thus will later
trigger the warnings inside invalidate_btree_folios().
---truncated---