Upstream information
Description
In the Linux kernel, the following vulnerability has been resolved: btrfs: protect folio::private when attaching extent buffer folios [BUG] Since v6.8 there are rare kernel crashes reported by various people, the common factor is bad page status error messages like this: BUG: Bad page state in process kswapd0 pfn:d6e840 page: refcount:0 mapcount:0 mapping:000000007512f4f2 index:0x2796c2c7c pfn:0xd6e840 aops:btree_aops ino:1 flags: 0x17ffffe0000008(uptodate|node=0|zone=2|lastcpupid=0x3fffff) page_type: 0xffffffff() raw: 0017ffffe0000008 dead000000000100 dead000000000122 ffff88826d0be4c0 raw: 00000002796c2c7c 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: non-NULL mapping [CAUSE] Commit 09e6cef19c9f ("btrfs: refactor alloc_extent_buffer() to allocate-then-attach method") changes the sequence when allocating a new extent buffer. Previously we always called grab_extent_buffer() under mapping->i_private_lock, to ensure the safety on modification on folio::private (which is a pointer to extent buffer for regular sectorsize). This can lead to the following race: Thread A is trying to allocate an extent buffer at bytenr X, with 4 4K pages, meanwhile thread B is trying to release the page at X + 4K (the second page of the extent buffer at X). Thread A | Thread B -----------------------------------+------------------------------------- | btree_release_folio() | | This is for the page at X + 4K, | | Not page X. | | alloc_extent_buffer() | |- release_extent_buffer() |- filemap_add_folio() for the | | |- atomic_dec_and_test(eb->refs) | page at bytenr X (the first | | | | page). | | | | Which returned -EEXIST. | | | | | | | |- filemap_lock_folio() | | | | Returned the first page locked. | | | | | | | |- grab_extent_buffer() | | | | |- atomic_inc_not_zero() | | | | | Returned false | | | | |- folio_detach_private() | | |- folio_detach_private() for X | |- folio_test_private() | | |- folio_test_private() | Returned true | | | Returned true |- folio_put() | |- folio_put() Now there are two puts on the same folio at folio X, leading to refcount underflow of the folio X, and eventually causing the BUG_ON() on the page->mapping. The condition is not that easy to hit: - The release must be triggered for the middle page of an eb If the release is on the same first page of an eb, page lock would kick in and prevent the race. - folio_detach_private() has a very small race window It's only between folio_test_private() and folio_clear_private(). That's exactly when mapping->i_private_lock is used to prevent such race, and commit 09e6cef19c9f ("btrfs: refactor alloc_extent_buffer() to allocate-then-attach method") screwed that up. At that time, I thought the page lock would kick in as filemap_release_folio() also requires the page to be locked, but forgot the filemap_release_folio() only locks one page, not all pages of an extent buffer. [FIX] Move all the code requiring i_private_lock into attach_eb_folio_to_filemap(), so that everything is done with proper lock protection. Furthermore to prevent future problems, add an extra lockdep_assert_locked() to ensure we're holding the proper lock. To reproducer that is able to hit the race (takes a few minutes with instrumented code inserting delays to alloc_extent_buffer()): #!/bin/sh drop_caches () { while(true); do echo 3 > /proc/sys/vm/drop_caches echo 1 > /proc/sys/vm/compact_memory done } run_tar () { while(true); do for x in `seq 1 80` ; do tar cf /dev/zero /mnt > /dev/null & done wait done } mkfs.btrfs -f -d single -m single ---truncated---SUSE information
Overall state of this security issue: Resolved
This issue is currently rated as having moderate severity.
| SUSE | |
|---|---|
| Base Score | 7 |
| Vector | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H |
| Attack Vector | Local |
| Attack Complexity | High |
| Privileges Required | Low |
| User Interaction | None |
| Scope | Unchanged |
| Confidentiality Impact | High |
| Integrity Impact | High |
| Availability Impact | High |
| CVSSv3 Version | 3.1 |
Status of this issue by product and package
Please note that this evaluation state might be work in progress, incomplete or outdated. Also information for service packs in the LTSS phase is only included for issues meeting the LTSS criteria. If in doubt, feel free to contact us for clarification. The updates are grouped by state of their lifecycle. SUSE product lifecycles are documented on the lifecycle page.
| Product(s) | Source package | State |
|---|---|---|
| Products under general support and receiving all security fixes. | ||
| SUSE Enterprise Storage 7.1 | kernel-default | Not affected |
| SUSE Enterprise Storage 7.1 | kernel-source | Not affected |
| SUSE Linux Enterprise Desktop 15 SP5 | kernel-default | Not affected |
| SUSE Linux Enterprise Desktop 15 SP5 | kernel-source | Not affected |
| SUSE Linux Enterprise Desktop 15 SP6 | kernel-default | Not affected |
| SUSE Linux Enterprise Desktop 15 SP6 | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 12 SP5 | kernel-default | Not affected |
| SUSE Linux Enterprise High Performance Computing 12 SP5 | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 12 SP5 | kernel-source-azure | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP5 | kernel-default | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP5 | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP5 | kernel-source-azure | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP6 | kernel-default | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP6 | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP6 | kernel-source-azure | Not affected |
| SUSE Linux Enterprise Micro 5.1 | kernel-default | Not affected |
| SUSE Linux Enterprise Micro 5.1 | kernel-rt | Not affected |
| SUSE Linux Enterprise Micro 5.1 | kernel-source-rt | Not affected |
| SUSE Linux Enterprise Micro 5.2 | kernel-default | Not affected |
| SUSE Linux Enterprise Micro 5.2 | kernel-rt | Not affected |
| SUSE Linux Enterprise Micro 5.2 | kernel-source-rt | Not affected |
| SUSE Linux Enterprise Micro 5.3 | kernel-default | Not affected |
| SUSE Linux Enterprise Micro 5.3 | kernel-rt | Not affected |
| SUSE Linux Enterprise Micro 5.3 | kernel-source-rt | Not affected |
| SUSE Linux Enterprise Micro 5.4 | kernel-default | Not affected |
| SUSE Linux Enterprise Micro 5.4 | kernel-rt | Not affected |
| SUSE Linux Enterprise Micro 5.4 | kernel-source-rt | Not affected |
| SUSE Linux Enterprise Micro 5.5 | kernel-source-rt | Not affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP5 | kernel-default | Not affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP5 | kernel-source | Not affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP6 | kernel-default | Not affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP6 | kernel-source | Not affected |
| SUSE Linux Enterprise Module for Development Tools 15 SP5 | kernel-default | Not affected |
| SUSE Linux Enterprise Module for Development Tools 15 SP5 | kernel-source | Not affected |
| SUSE Linux Enterprise Module for Development Tools 15 SP6 | kernel-default | Not affected |
| SUSE Linux Enterprise Module for Development Tools 15 SP6 | kernel-source | Not affected |
| SUSE Linux Enterprise Module for Public Cloud 15 SP5 | kernel-source-azure | Not affected |
| SUSE Linux Enterprise Module for Public Cloud 15 SP6 | kernel-source-azure | Not affected |
| SUSE Linux Enterprise Real Time 12 SP5 | kernel-source-rt | Not affected |
| SUSE Linux Enterprise Real Time 15 SP5 | kernel-source-rt | Not affected |
| SUSE Linux Enterprise Real Time 15 SP6 | kernel-source-rt | Not affected |
| SUSE Linux Enterprise Server 12 SP5 | kernel-default | Not affected |
| SUSE Linux Enterprise Server 12 SP5 | kernel-source | Not affected |
| SUSE Linux Enterprise Server 12 SP5 | kernel-source-azure | Not affected |
| SUSE Linux Enterprise Server 15 SP5 | kernel-default | Not affected |
| SUSE Linux Enterprise Server 15 SP5 | kernel-source | Not affected |
| SUSE Linux Enterprise Server 15 SP5 | kernel-source-azure | Not affected |
| SUSE Linux Enterprise Server 15 SP6 | kernel-default | Not affected |
| SUSE Linux Enterprise Server 15 SP6 | kernel-source | Not affected |
| SUSE Linux Enterprise Server 15 SP6 | kernel-source-azure | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 12 SP5 | kernel-default | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 12 SP5 | kernel-source | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 12 SP5 | kernel-source-azure | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP5 | kernel-default | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP5 | kernel-source | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP5 | kernel-source-azure | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP6 | kernel-default | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP6 | kernel-source | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP6 | kernel-source-azure | Not affected |
| SUSE Manager Proxy 4.3 | kernel-default | Not affected |
| SUSE Manager Proxy 4.3 | kernel-source | Not affected |
| SUSE Manager Retail Branch Server 4.3 | kernel-default | Not affected |
| SUSE Manager Retail Branch Server 4.3 | kernel-source | Not affected |
| SUSE Manager Server 4.3 | kernel-default | Not affected |
| SUSE Manager Server 4.3 | kernel-source | Not affected |
| SUSE Real Time Module 15 SP5 | kernel-source-rt | Not affected |
| SUSE Real Time Module 15 SP6 | kernel-source-rt | Not affected |
| openSUSE Leap 15.5 | kernel-default | Not affected |
| openSUSE Leap 15.5 | kernel-source | Not affected |
| openSUSE Leap 15.5 | kernel-source-azure | Not affected |
| openSUSE Leap 15.5 | kernel-source-rt | Not affected |
| openSUSE Leap 15.6 | kernel-default | Not affected |
| openSUSE Leap 15.6 | kernel-source | Not affected |
| openSUSE Leap 15.6 | kernel-source-azure | Not affected |
| openSUSE Leap 15.6 | kernel-source-rt | Not affected |
| Products under Long Term Service Pack support and receiving important and critical security fixes. | ||
| SUSE Linux Enterprise Desktop 15 SP4 | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP2 | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP2-ESPOS | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP2-LTSS | kernel-default | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP2-LTSS | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3 | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3-ESPOS | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3-LTSS | kernel-default | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3-LTSS | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP4 | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS | kernel-default | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS | kernel-default | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS | kernel-source | Not affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP2 | kernel-source | Not affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP3 | kernel-source | Not affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP4 | kernel-source | Not affected |
| SUSE Linux Enterprise Module for Development Tools 15 SP2 | kernel-source | Not affected |
| SUSE Linux Enterprise Module for Development Tools 15 SP3 | kernel-source | Not affected |
| SUSE Linux Enterprise Module for Development Tools 15 SP4 | kernel-source | Not affected |
| SUSE Linux Enterprise Server 11 SP4 LTSS EXTREME CORE | kernel-default | Not affected |
| SUSE Linux Enterprise Server 11 SP4 LTSS EXTREME CORE | kernel-source | Not affected |
| SUSE Linux Enterprise Server 15 SP2 | kernel-source | Not affected |
| SUSE Linux Enterprise Server 15 SP2-LTSS | kernel-default | Not affected |
| SUSE Linux Enterprise Server 15 SP2-LTSS | kernel-source | Not affected |
| SUSE Linux Enterprise Server 15 SP3 | kernel-source | Not affected |
| SUSE Linux Enterprise Server 15 SP3-LTSS | kernel-default | Not affected |
| SUSE Linux Enterprise Server 15 SP3-LTSS | kernel-source | Not affected |
| SUSE Linux Enterprise Server 15 SP4 | kernel-source | Not affected |
| SUSE Linux Enterprise Server 15 SP4-LTSS | kernel-default | Not affected |
| SUSE Linux Enterprise Server 15 SP4-LTSS | kernel-source | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP2 | kernel-default | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP2 | kernel-source | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP3 | kernel-default | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP3 | kernel-source | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP4 | kernel-default | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP4 | kernel-source | Not affected |
| Products past their end of life and not receiving proactive updates anymore. | ||
| HPE Helion OpenStack 8 | kernel-source | Not affected |
| SUSE CaaS Platform 4.0 | kernel-source | Not affected |
| SUSE Enterprise Storage 6 | kernel-source | Not affected |
| SUSE Enterprise Storage 7 | kernel-source | Not affected |
| SUSE Linux Enterprise Desktop 12 SP3 | kernel-source | Not affected |
| SUSE Linux Enterprise Desktop 12 SP4 | kernel-source | Not affected |
| SUSE Linux Enterprise Desktop 15 | kernel-source | Not affected |
| SUSE Linux Enterprise Desktop 15 SP1 | kernel-source | Not affected |
| SUSE Linux Enterprise Desktop 15 SP2 | kernel-source | Not affected |
| SUSE Linux Enterprise Desktop 15 SP3 | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP1 | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP1-ESPOS | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP1-LTSS | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 15-ESPOS | kernel-source | Not affected |
| SUSE Linux Enterprise High Performance Computing 15-LTSS | kernel-source | Not affected |
| SUSE Linux Enterprise Micro 5.0 | kernel-default | Not affected |
| SUSE Linux Enterprise Module for Basesystem 15 | kernel-source | Not affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP1 | kernel-source | Not affected |
| SUSE Linux Enterprise Module for Development Tools 15 | kernel-source | Not affected |
| SUSE Linux Enterprise Module for Development Tools 15 SP1 | kernel-source | Not affected |
| SUSE Linux Enterprise Real Time 15 SP2 | kernel-source | Not affected |
| SUSE Linux Enterprise Real Time 15 SP3 | kernel-source | Not affected |
| SUSE Linux Enterprise Real Time 15 SP3 | kernel-source-rt | Not affected |
| SUSE Linux Enterprise Real Time 15 SP4 | kernel-source | Not affected |
| SUSE Linux Enterprise Real Time 15 SP4 | kernel-source-rt | Not affected |
| SUSE Linux Enterprise Server 11 SP4 | kernel-source | Not affected |
| SUSE Linux Enterprise Server 11 SP4 LTSS | kernel-default | Not affected |
| SUSE Linux Enterprise Server 11 SP4 LTSS | kernel-source | Not affected |
| SUSE Linux Enterprise Server 11 SP4-LTSS | kernel-source | Not affected |
| SUSE Linux Enterprise Server 12 SP3 | kernel-source | Not affected |
| SUSE Linux Enterprise Server 12 SP3-BCL | kernel-source | Not affected |
| SUSE Linux Enterprise Server 12 SP3-ESPOS | kernel-source | Not affected |
| SUSE Linux Enterprise Server 12 SP3-LTSS | kernel-source | Not affected |
| SUSE Linux Enterprise Server 12 SP4 | kernel-source | Not affected |
| SUSE Linux Enterprise Server 12 SP4-ESPOS | kernel-source | Not affected |
| SUSE Linux Enterprise Server 12 SP4-LTSS | kernel-default | Not affected |
| SUSE Linux Enterprise Server 12 SP4-LTSS | kernel-source | Not affected |
| SUSE Linux Enterprise Server 15 | kernel-source | Not affected |
| SUSE Linux Enterprise Server 15 SP1 | kernel-source | Not affected |
| SUSE Linux Enterprise Server 15 SP1-BCL | kernel-source | Not affected |
| SUSE Linux Enterprise Server 15 SP1-LTSS | kernel-default | Not affected |
| SUSE Linux Enterprise Server 15 SP1-LTSS | kernel-source | Not affected |
| SUSE Linux Enterprise Server 15 SP2-BCL | kernel-source | Not affected |
| SUSE Linux Enterprise Server 15 SP3-BCL | kernel-source | Not affected |
| SUSE Linux Enterprise Server 15-LTSS | kernel-default | Not affected |
| SUSE Linux Enterprise Server 15-LTSS | kernel-source | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 12 SP3 | kernel-source | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 12 SP4 | kernel-default | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 12 SP4 | kernel-source | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 15 | kernel-source | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP1 | kernel-source | Not affected |
| SUSE Manager Proxy 4.0 | kernel-source | Not affected |
| SUSE Manager Proxy 4.1 | kernel-source | Not affected |
| SUSE Manager Proxy 4.2 | kernel-source | Not affected |
| SUSE Manager Retail Branch Server 4.0 | kernel-source | Not affected |
| SUSE Manager Retail Branch Server 4.1 | kernel-source | Not affected |
| SUSE Manager Retail Branch Server 4.2 | kernel-source | Not affected |
| SUSE Manager Server 4.0 | kernel-source | Not affected |
| SUSE Manager Server 4.1 | kernel-source | Not affected |
| SUSE Manager Server 4.2 | kernel-source | Not affected |
| SUSE OpenStack Cloud 8 | kernel-source | Not affected |
| SUSE OpenStack Cloud 9 | kernel-source | Not affected |
| SUSE OpenStack Cloud Crowbar 8 | kernel-source | Not affected |
| SUSE OpenStack Cloud Crowbar 9 | kernel-source | Not affected |
| SUSE Real Time Module 15 SP3 | kernel-source-rt | Not affected |
| SUSE Real Time Module 15 SP4 | kernel-source-rt | Not affected |
SUSE Timeline for this CVE
CVE page created: Tue Jun 25 18:00:15 2024CVE page last modified: Wed Jun 26 18:07:56 2024