{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2024-26658", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2024-26658", "idYear": 2024, "status": "PUBLISHED", "publishedAt": "2024-04-02T06:22:08.468Z", "updatedAt": "2026-05-11T20:01:39.895Z", "importedAt": "2026-10-24T01:57:07.518Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "bcachefs: grab s_umount only if snapshotting", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nbcachefs: grab s_umount only if snapshotting\n\nWhen I was testing mongodb over bcachefs with compression,\nthere is a lockdep warning when snapshotting mongodb data volume.\n\n$ cat test.sh\nprog=bcachefs\n\n$prog subvolume create /mnt/data\n$prog subvolume create /mnt/data/snapshots\n\nwhile true;do\n $prog subvolume snapshot /mnt/data /mnt/data/snapshots/$(date +%s)\n sleep 1s\ndone\n\n$ cat /etc/mongodb.conf\nsystemLog:\n destination: file\n logAppend: true\n path: /mnt/data/mongod.log\n\nstorage:\n dbPath: /mnt/data/\n\nlockdep reports:\n[ 3437.452330] ======================================================\n[ 3437.452750] WARNING: possible circular locking dependency detected\n[ 3437.453168] 6.7.0-rc7-custom+ #85 Tainted: G E\n[ 3437.453562] ------------------------------------------------------\n[ 3437.453981] bcachefs/35533 is trying to acquire lock:\n[ 3437.454325] ffffa0a02b2b1418 (sb_writers#10){.+.+}-{0:0}, at: filename_create+0x62/0x190\n[ 3437.454875]\n but task is already holding lock:\n[ 3437.455268] ffffa0a02b2b10e0 (&type->s_umount_key#48){.+.+}-{3:3}, at: bch2_fs_file_ioctl+0x232/0xc90 [bcachefs]\n[ 3437.456009]\n which lock already depends on the new lock.\n\n[ 3437.456553]\n the existing dependency chain (in reverse order) is:\n[ 3437.457054]\n -> #3 (&type->s_umount_key#48){.+.+}-{3:3}:\n[ 3437.457507] down_read+0x3e/0x170\n[ 3437.457772] bch2_fs_file_ioctl+0x232/0xc90 [bcachefs]\n[ 3437.458206] __x64_sys_ioctl+0x93/0xd0\n[ 3437.458498] do_syscall_64+0x42/0xf0\n[ 3437.458779] entry_SYSCALL_64_after_hwframe+0x6e/0x76\n[ 3437.459155]\n -> #2 (&c->snapshot_create_lock){++++}-{3:3}:\n[ 3437.459615] down_read+0x3e/0x170\n[ 3437.459878] bch2_truncate+0x82/0x110 [bcachefs]\n[ 3437.460276] bchfs_truncate+0x254/0x3c0 [bcachefs]\n[ 3437.460686] notify_change+0x1f1/0x4a0\n[ 3437.461283] do_truncate+0x7f/0xd0\n[ 3437.461555] path_openat+0xa57/0xce0\n[ 3437.461836] do_filp_open+0xb4/0x160\n[ 3437.462116] do_sys_openat2+0x91/0xc0\n[ 3437.462402] __x64_sys_openat+0x53/0xa0\n[ 3437.462701] do_syscall_64+0x42/0xf0\n[ 3437.462982] entry_SYSCALL_64_after_hwframe+0x6e/0x76\n[ 3437.463359]\n -> #1 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}:\n[ 3437.463843] down_write+0x3b/0xc0\n[ 3437.464223] bch2_write_iter+0x5b/0xcc0 [bcachefs]\n[ 3437.464493] vfs_write+0x21b/0x4c0\n[ 3437.464653] ksys_write+0x69/0xf0\n[ 3437.464839] do_syscall_64+0x42/0xf0\n[ 3437.465009] entry_SYSCALL_64_after_hwframe+0x6e/0x76\n[ 3437.465231]\n -> #0 (sb_writers#10){.+.+}-{0:0}:\n[ 3437.465471] __lock_acquire+0x1455/0x21b0\n[ 3437.465656] lock_acquire+0xc6/0x2b0\n[ 3437.465822] mnt_want_write+0x46/0x1a0\n[ 3437.465996] filename_create+0x62/0x190\n[ 3437.466175] user_path_create+0x2d/0x50\n[ 3437.466352] bch2_fs_file_ioctl+0x2ec/0xc90 [bcachefs]\n[ 3437.466617] __x64_sys_ioctl+0x93/0xd0\n[ 3437.466791] do_syscall_64+0x42/0xf0\n[ 3437.466957] entry_SYSCALL_64_after_hwframe+0x6e/0x76\n[ 3437.467180]\n other info that might help us debug this:\n\n[ 3437.469670] 2 locks held by bcachefs/35533:\n other info that might help us debug this:\n\n[ 3437.467507] Chain exists of:\n sb_writers#10 --> &c->snapshot_create_lock --> &type->s_umount_key#48\n\n[ 3437.467979] Possible unsafe locking scenario:\n\n[ 3437.468223] CPU0 CPU1\n[ 3437.468405] ---- ----\n[ 3437.468585] rlock(&type->s_umount_key#48);\n[ 3437.468758] lock(&c->snapshot_create_lock);\n[ 3437.469030] lock(&type->s_umount_key#48);\n[ 3437.469291] rlock(sb_writers#10);\n[ 3437.469434]\n *** DEADLOCK ***\n\n[ 3437.469\n---truncated---", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "1c6fdbd8f2465ddfb73a01ec620cbf3d14044e1a", "status": "affected", "versionType": "git", "lessThan": "5b41d3fd04c6757b9c2a60a0c5b2609cae9999df" }, { "version": "1c6fdbd8f2465ddfb73a01ec620cbf3d14044e1a", "status": "affected", "versionType": "git", "lessThan": "2acc59dd88d27ad69b66ded80df16c042b04eeec" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "6.7", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "6.7" }, { "version": "6.7.5", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.7.*" }, { "version": "6.8", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }