From: Boris Burkov boris@bur.io

mainline inclusion from mainline-v6.11-rc3 commit 30479f31d44d47ed00ae0c7453d9b253537005b2 bugzilla: https://gitee.com/src-openeuler/kernel/issues/IARV5C CVE: CVE-2024-46733

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

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In the buffered write path, the dirty page owns the qgroup reserve until it creates an ordered_extent.

Therefore, any errors that occur before the ordered_extent is created must free that reservation, or else the space is leaked. The fstest generic/475 exercises various IO error paths, and is able to trigger errors in cow_file_range where we fail to get to allocating the ordered extent. Note that because we *do* clear delalloc, we are likely to remove the inode from the delalloc list, so the inodes/pages to not have invalidate/launder called on them in the commit abort path.

This results in failures at the unmount stage of the test that look like:

BTRFS: error (device dm-8 state EA) in cleanup_transaction:2018: errno=-5 IO failure BTRFS: error (device dm-8 state EA) in btrfs_replace_file_extents:2416: errno=-5 IO failure BTRFS warning (device dm-8 state EA): qgroup 0/5 has unreleased space, type 0 rsv 28672 ------------[ cut here ]------------ WARNING: CPU: 3 PID: 22588 at fs/btrfs/disk-io.c:4333 close_ctree+0x222/0x4d0 [btrfs] Modules linked in: btrfs blake2b_generic libcrc32c xor zstd_compress raid6_pq CPU: 3 PID: 22588 Comm: umount Kdump: loaded Tainted: G W 6.10.0-rc7-gab56fde445b8 #21 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014 RIP: 0010:close_ctree+0x222/0x4d0 [btrfs] RSP: 0018:ffffb4465283be00 EFLAGS: 00010202 RAX: 0000000000000001 RBX: ffffa1a1818e1000 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffffb4465283bbe0 RDI: ffffa1a19374fcb8 RBP: ffffa1a1818e13c0 R08: 0000000100028b16 R09: 0000000000000000 R10: 0000000000000003 R11: 0000000000000003 R12: ffffa1a18ad7972c R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f9168312b80(0000) GS:ffffa1a4afcc0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f91683c9140 CR3: 000000010acaa000 CR4: 00000000000006f0 Call Trace: <TASK> ? close_ctree+0x222/0x4d0 [btrfs] ? __warn.cold+0x8e/0xea ? close_ctree+0x222/0x4d0 [btrfs] ? report_bug+0xff/0x140 ? handle_bug+0x3b/0x70 ? exc_invalid_op+0x17/0x70 ? asm_exc_invalid_op+0x1a/0x20 ? close_ctree+0x222/0x4d0 [btrfs] generic_shutdown_super+0x70/0x160 kill_anon_super+0x11/0x40 btrfs_kill_super+0x11/0x20 [btrfs] deactivate_locked_super+0x2e/0xa0 cleanup_mnt+0xb5/0x150 task_work_run+0x57/0x80 syscall_exit_to_user_mode+0x121/0x130 do_syscall_64+0xab/0x1a0 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f916847a887 ---[ end trace 0000000000000000 ]--- BTRFS error (device dm-8 state EA): qgroup reserved space leaked

Cases 2 and 3 in the out_reserve path both pertain to this type of leak and must free the reserved qgroup data. Because it is already an error path, I opted not to handle the possible errors in btrfs_free_qgroup_data.

Reviewed-by: Qu Wenruo wqu@suse.com Signed-off-by: Boris Burkov boris@bur.io Signed-off-by: David Sterba dsterba@suse.com Conflicts: fs/btrfs/inode.c [Just context differences.] Signed-off-by: Yifan Qiao qiaoyifan4@huawei.com --- fs/btrfs/inode.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 5ddee801a830..5c34909ea95b 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -1543,6 +1543,7 @@ static noinline int cow_file_range(struct btrfs_inode *inode, locked_page, clear_bits, page_ops); + btrfs_qgroup_free_data(inode, NULL, start, cur_alloc_size, NULL); start += cur_alloc_size; }

@@ -1556,6 +1557,7 @@ static noinline int cow_file_range(struct btrfs_inode *inode, clear_bits |= EXTENT_CLEAR_DATA_RESV; extent_clear_unlock_delalloc(inode, start, end, locked_page, clear_bits, page_ops); + btrfs_qgroup_free_data(inode, NULL, start, cur_alloc_size, NULL); } return ret; } @@ -2219,13 +2221,15 @@ static noinline int run_delalloc_nocow(struct btrfs_inode *inode, */ if (cow_start != (u64)-1) cur_offset = cow_start; - if (cur_offset < end) + if (cur_offset < end) { extent_clear_unlock_delalloc(inode, cur_offset, end, locked_page, EXTENT_LOCKED | EXTENT_DELALLOC | EXTENT_DEFRAG | EXTENT_DO_ACCOUNTING, PAGE_UNLOCK | PAGE_START_WRITEBACK | PAGE_END_WRITEBACK); + btrfs_qgroup_free_data(inode, NULL, cur_offset, end - cur_offset + 1, NULL); + } btrfs_free_path(path); return ret; }