In the Linux kernel, the following vulnerability has been resolved:
ext4: fix bug_on in __es_tree_search caused by bad quota inode
We got a issue as fllows: ================================================================== kernel BUG at fs/ext4/extents_status.c:202! invalid opcode: 0000 [#1] PREEMPT SMP CPU: 1 PID: 810 Comm: mount Not tainted 6.1.0-rc1-next-g9631525255e3 #352 RIP: 0010:__es_tree_search.isra.0+0xb8/0xe0 RSP: 0018:ffffc90001227900 EFLAGS: 00010202 RAX: 0000000000000000 RBX: 0000000077512a0f RCX: 0000000000000000 RDX: 0000000000000002 RSI: 0000000000002a10 RDI: ffff8881004cd0c8 RBP: ffff888177512ac8 R08: 47ffffffffffffff R09: 0000000000000001 R10: 0000000000000001 R11: 00000000000679af R12: 0000000000002a10 R13: ffff888177512d88 R14: 0000000077512a10 R15: 0000000000000000 FS: 00007f4bd76dbc40(0000)GS:ffff88842fd00000(0000)knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005653bf993cf8 CR3: 000000017bfdf000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> ext4_es_cache_extent+0xe2/0x210 ext4_cache_extents+0xd2/0x110 ext4_find_extent+0x5d5/0x8c0 ext4_ext_map_blocks+0x9c/0x1d30 ext4_map_blocks+0x431/0xa50 ext4_getblk+0x82/0x340 ext4_bread+0x14/0x110 ext4_quota_read+0xf0/0x180 v2_read_header+0x24/0x90 v2_check_quota_file+0x2f/0xa0 dquot_load_quota_sb+0x26c/0x760 dquot_load_quota_inode+0xa5/0x190 ext4_enable_quotas+0x14c/0x300 __ext4_fill_super+0x31cc/0x32c0 ext4_fill_super+0x115/0x2d0 get_tree_bdev+0x1d2/0x360 ext4_get_tree+0x19/0x30 vfs_get_tree+0x26/0xe0 path_mount+0x81d/0xfc0 do_mount+0x8d/0xc0 __x64_sys_mount+0xc0/0x160 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x63/0xcd </TASK> ==================================================================
Above issue may happen as follows: ------------------------------------- ext4_fill_super ext4_orphan_cleanup ext4_enable_quotas ext4_quota_enable ext4_iget --> get error inode <5> ext4_ext_check_inode --> Wrong imode makes it escape inspection make_bad_inode(inode) --> EXT4_BOOT_LOADER_INO set imode dquot_load_quota_inode vfs_setup_quota_inode --> check pass dquot_load_quota_sb v2_check_quota_file v2_read_header ext4_quota_read ext4_bread ext4_getblk ext4_map_blocks ext4_ext_map_blocks ext4_find_extent ext4_cache_extents ext4_es_cache_extent __es_tree_search.isra.0 ext4_es_end --> Wrong extents trigger BUG_ON
In the above issue, s_usr_quota_inum is set to 5, but inode<5> contains incorrect imode and disordered extents. Because 5 is EXT4_BOOT_LOADER_INO, the ext4_ext_check_inode check in the ext4_iget function can be bypassed, finally, the extents that are not checked trigger the BUG_ON in the __es_tree_search function. To solve this issue, check whether the inode is bad_inode in vfs_setup_quota_inode().
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Amazon Linux Ami 2 | — | Upgrade bpftoolUpgrade kernel-livepatch-5.10.165-143.735Upgrade kernel-debuginfo-common-x86_64Upgrade kernel-toolsUpgrade python-perfUpgrade kernelUpgrade bpftool-debuginfoUpgrade kernel-debuginfo-common-aarch64Upgrade kernel-develUpgrade perfUpgrade kernel-livepatch-5.15.90-54.138Upgrade perf-debuginfoUpgrade kernel-debuginfoUpgrade kernel-headersUpgrade python-perf-debuginfoUpgrade kernel-tools-debuginfoUpgrade kernel-tools-devel | May 20, 2026 | May 20, 2026 |
| Debian | — | Upgrade linux | Dec 29, 2025 | Dec 29, 2025 |
| Huawei Euleros 2_0_sp13 | — | Upgrade kernel-abi-stablelistsUpgrade python3-perfUpgrade kernelUpgrade kernel-toolsUpgrade kernel-tools-libsUpgrade bpftool | Mar 10, 2026 | Mar 10, 2026 |
| Redhat_linux | — | No solution exists | Jul 17, 2026 | Dec 24, 2025 |
| Ubuntu | — | Upgrade linux-lowlatency-hwe-5.15Upgrade linux-iotUpgrade linux-raspiUpgrade linux-gcp-5.15Upgrade linux-xilinx-zynqmpUpgrade linux-gkeUpgrade linux-nvidiaUpgrade linux-azureUpgrade linux-raspi-5.4Upgrade linux-realtimeUpgrade linux-bluefieldUpgrade linux-intel-iotg-5.15Upgrade linux-aws-5.4Upgrade linux-hwe-5.15Upgrade linux-intel-iotgUpgrade linux-azure-5.4Upgrade linux-kvmUpgrade linux-aws-5.15Upgrade linux-lowlatencyUpgrade linux-oracleUpgrade linux-riscv-5.15Upgrade linux-azure-fde-5.15Upgrade linux-oracle-5.4Upgrade linux-azure-5.15Upgrade linux-oracle-5.15Upgrade linux-intel-iot-realtimeUpgrade linux-ibm-5.4Upgrade linux-ibmUpgrade linux-gcpUpgrade linux-nvidia-tegra-5.15Upgrade linux-azure-fipsUpgrade linux-awsUpgrade linux-hwe-5.4Upgrade linux-gkeopUpgrade linux-aws-fipsUpgrade linux-fipsUpgrade linux-gcp-5.4Upgrade linuxUpgrade linux-gcp-fips | Jan 6, 2026 | Dec 24, 2025 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | May 27, 2026 | Dec 24, 2025 |
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