Security update for the Linux Kernel (Live Patch 10 for SLE 15 SP6) SUSE Patch security@suse.de SUSE Security Team SUSE-SU-2025:02514-1 Final 1 1 2025-07-24T18:04:14Z current 2025-07-24T18:04:14Z 2025-07-24T18:04:14Z cve-database/bin/generate-cvrf.pl 2017-02-24T01:00:00Z Security update for the Linux Kernel (Live Patch 10 for SLE 15 SP6) This update for the Linux Kernel 6.4.0-150600_23_47 fixes several issues. The following security issue was fixed: - CVE-2025-22115: btrfs: fix block group refcount race in btrfs_create_pending_block_groups() (bsc#1241579). The CVRF data is provided by SUSE under the Creative Commons License 4.0 with Attribution (CC-BY-4.0). SUSE-2025-2514,SUSE-SLE-Module-Live-Patching-15-SP6-2025-2514 Copyright SUSE LLC under the Creative Commons License 4.0 with Attribution (CC-BY-4.0) https://www.suse.com/support/update/announcement/2025/suse-su-202502514-1/ Link for SUSE-SU-2025:02514-1 https://lists.suse.com/pipermail/sle-updates/2025-July/040904.html E-Mail link for SUSE-SU-2025:02514-1 https://www.suse.com/support/security/rating/ SUSE Security Ratings https://bugzilla.suse.com/1241579 SUSE Bug 1241579 https://bugzilla.suse.com/1244337 SUSE Bug 1244337 https://www.suse.com/security/cve/CVE-2025-22115/ SUSE CVE CVE-2025-22115 page SUSE Linux Enterprise Live Patching 15 SP6 kernel-livepatch-6_4_0-150600_23_47-default-2-150600.2.1 kernel-livepatch-6_4_0-150600_23_47-default-2-150600.2.1 as a component of SUSE Linux Enterprise Live Patching 15 SP6 In the Linux kernel, the following vulnerability has been resolved: btrfs: fix block group refcount race in btrfs_create_pending_block_groups() Block group creation is done in two phases, which results in a slightly unintuitive property: a block group can be allocated/deallocated from after btrfs_make_block_group() adds it to the space_info with btrfs_add_bg_to_space_info(), but before creation is completely completed in btrfs_create_pending_block_groups(). As a result, it is possible for a block group to go unused and have 'btrfs_mark_bg_unused' called on it concurrently with 'btrfs_create_pending_block_groups'. This causes a number of issues, which were fixed with the block group flag 'BLOCK_GROUP_FLAG_NEW'. However, this fix is not quite complete. Since it does not use the unused_bg_lock, it is possible for the following race to occur: btrfs_create_pending_block_groups btrfs_mark_bg_unused if list_empty // false list_del_init clear_bit else if (test_bit) // true list_move_tail And we get into the exact same broken ref count and invalid new_bgs state for transaction cleanup that BLOCK_GROUP_FLAG_NEW was designed to prevent. The broken refcount aspect will result in a warning like: [1272.943527] refcount_t: underflow; use-after-free. [1272.943967] WARNING: CPU: 1 PID: 61 at lib/refcount.c:28 refcount_warn_saturate+0xba/0x110 [1272.944731] Modules linked in: btrfs virtio_net xor zstd_compress raid6_pq null_blk [last unloaded: btrfs] [1272.945550] CPU: 1 UID: 0 PID: 61 Comm: kworker/u32:1 Kdump: loaded Tainted: G W 6.14.0-rc5+ #108 [1272.946368] Tainted: [W]=WARN [1272.946585] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014 [1272.947273] Workqueue: btrfs_discard btrfs_discard_workfn [btrfs] [1272.947788] RIP: 0010:refcount_warn_saturate+0xba/0x110 [1272.949532] RSP: 0018:ffffbf1200247df0 EFLAGS: 00010282 [1272.949901] RAX: 0000000000000000 RBX: ffffa14b00e3f800 RCX: 0000000000000000 [1272.950437] RDX: 0000000000000000 RSI: ffffbf1200247c78 RDI: 00000000ffffdfff [1272.950986] RBP: ffffa14b00dc2860 R08: 00000000ffffdfff R09: ffffffff90526268 [1272.951512] R10: ffffffff904762c0 R11: 0000000063666572 R12: ffffa14b00dc28c0 [1272.952024] R13: 0000000000000000 R14: ffffa14b00dc2868 R15: 000001285dcd12c0 [1272.952850] FS: 0000000000000000(0000) GS:ffffa14d33c40000(0000) knlGS:0000000000000000 [1272.953458] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [1272.953931] CR2: 00007f838cbda000 CR3: 000000010104e000 CR4: 00000000000006f0 [1272.954474] Call Trace: [1272.954655] <TASK> [1272.954812] ? refcount_warn_saturate+0xba/0x110 [1272.955173] ? __warn.cold+0x93/0xd7 [1272.955487] ? refcount_warn_saturate+0xba/0x110 [1272.955816] ? report_bug+0xe7/0x120 [1272.956103] ? handle_bug+0x53/0x90 [1272.956424] ? exc_invalid_op+0x13/0x60 [1272.956700] ? asm_exc_invalid_op+0x16/0x20 [1272.957011] ? refcount_warn_saturate+0xba/0x110 [1272.957399] btrfs_discard_cancel_work.cold+0x26/0x2b [btrfs] [1272.957853] btrfs_put_block_group.cold+0x5d/0x8e [btrfs] [1272.958289] btrfs_discard_workfn+0x194/0x380 [btrfs] [1272.958729] process_one_work+0x130/0x290 [1272.959026] worker_thread+0x2ea/0x420 [1272.959335] ? __pfx_worker_thread+0x10/0x10 [1272.959644] kthread+0xd7/0x1c0 [1272.959872] ? __pfx_kthread+0x10/0x10 [1272.960172] ret_from_fork+0x30/0x50 [1272.960474] ? __pfx_kthread+0x10/0x10 [1272.960745] ret_from_fork_asm+0x1a/0x30 [1272.961035] </TASK> [1272.961238] ---[ end trace 0000000000000000 ]--- Though we have seen them in the async discard workfn as well. It is most likely to happen after a relocation finishes which cancels discard, tears down the block group, etc. Fix this fully by taking the lock arou ---truncated--- CVE-2025-22115 SUSE Linux Enterprise Live Patching 15 SP6:kernel-livepatch-6_4_0-150600_23_47-default-2-150600.2.1 important To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch". https://www.suse.com/support/update/announcement/2025/suse-su-202502514-1/ https://www.suse.com/security/cve/CVE-2025-22115.html CVE-2025-22115 https://bugzilla.suse.com/1241578 SUSE Bug 1241578 https://bugzilla.suse.com/1241579 SUSE Bug 1241579