CVE-2023-53865: btrfs: fix warning when putting transaction with qgroups enabled after abort
In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix warning when putting transaction with qgroups enabled after abort
If we have a transaction abort with qgroups enabled we get a warning triggered when doing the final put on the transaction, like this:
[552.6789] ------------[ cut here ]------------ [552.6815] WARNING: CPU: 4 PID: 81745 at fs/btrfs/transaction.c:144 btrfsputtransaction+0x123/0x130 [btrfs] [552.6817] Modules linked in: btrfs blake2bgeneric xor (...) [552.6819] CPU: 4 PID: 81745 Comm: btrfs-transacti Tainted: G W 6.4.0-rc6-btrfs-next-134+ #1 [552.6819] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014 [552.6819] RIP: 0010:btrfsputtransaction+0x123/0x130 [btrfs] [552.6821] Code: bd a0 01 00 (...) [552.6821] RSP: 0018:ffffa168c0527e28 EFLAGS: 00010286 [552.6821] RAX: ffff936042caed00 RBX: ffff93604a3eb448 RCX: 0000000000000000 [552.6821] RDX: ffff93606421b028 RSI: ffffffff92ff0878 RDI: ffff93606421b010 [552.6821] RBP: ffff93606421b000 R08: 0000000000000000 R09: ffffa168c0d07c20 [552.6821] R10: 0000000000000000 R11: ffff93608dc52950 R12: ffffa168c0527e70 [552.6821] R13: ffff93606421b000 R14: ffff93604a3eb420 R15: ffff93606421b028 [552.6821] FS: 0000000000000000(0000) GS:ffff93675fb00000(0000) knlGS:0000000000000000 [552.6821] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [552.6821] CR2: 0000558ad262b000 CR3: 000000014feda005 CR4: 0000000000370ee0 [552.6822] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [552.6822] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [552.6822] Call Trace: [552.6822] <TASK> [552.6822] ? warn+0x80/0x130 [552.6822] ? btrfsputtransaction+0x123/0x130 [btrfs] [552.6824] ? reportbug+0x1f4/0x200 [552.6824] ? handlebug+0x42/0x70 [552.6824] ? excinvalidop+0x14/0x70 [552.6824] ? asmexcinvalidop+0x16/0x20 [552.6824] ? btrfsputtransaction+0x123/0x130 [btrfs] [552.6826] btrfscleanuptransaction+0xe7/0x5e0 [btrfs] [552.6828] ? rawspinunlockirqrestore+0x23/0x40 [552.6828] ? trytowakeup+0x94/0x5e0 [552.6828] ? pfxprocesstimeout+0x10/0x10 [552.6828] transactionkthread+0x103/0x1d0 [btrfs] [552.6830] ? pfxtransactionkthread+0x10/0x10 [btrfs] [552.6832] kthread+0xee/0x120 [552.6832] ? pfxkthread+0x10/0x10 [552.6832] retfromfork+0x29/0x50 [552.6832] </TASK> [552.6832] ---[ end trace 0000000000000000 ]---
This corresponds to this line of code:
void btrfsputtransaction(struct btrfstransaction transaction) { (...) WARNON(!RBEMPTYROOT( &transaction->delayedrefs.dirtyextentroot)); (...) }
The warning happens because btrfsqgroupdestroyextentrecords(), called in the transaction abort path, we free all entries from the rbtree "dirtyextentroot" with rbtreepostorderforeachentrysafe(), but we don't actually empty the rbtree - it's still pointing to nodes that were freed.
So set the rbtree's root node to NULL to avoid this warning (assign RBROOT).
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2023-53865?
CVE-2023-53865 has a severity rating of medium as it involves a warning message during transaction handling with Btrfs in the Linux kernel.
How do I fix CVE-2023-53865?
To fix CVE-2023-53865, update your Linux kernel to version 6.4.0-rc7 or later.
What causes the warning in CVE-2023-53865?
The warning in CVE-2023-53865 is caused by an issue during the final put on a transaction when qgroups are enabled and a transaction abort occurs.
Which versions of the Linux kernel are affected by CVE-2023-53865?
CVE-2023-53865 affects Linux kernel versions up to and including 6.4.0-rc6.
Is CVE-2023-53865 related to Btrfs functionality?
Yes, CVE-2023-53865 specifically pertains to a warning generated in the Btrfs filesystem when handling transactions.