CVE-2026-74318
In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix deadlock cloning inline extent when using flushoncommit
In commit b48c980b6a7e ("btrfs: fix deadlock between reflink and transaction commit when using flushoncommit") a deadlock was fixed between reflinks and transaction commits when the fs is mounted with the flushoncommit option. This happened when we had to copy an inline extent's data to the destination file. However the issue was fixed only for the case where the destination offset is 0, it missed the case when the offset is greater than zero.
Fix this by ensuring we get i_size update whenever we copied an inline extent's data into the destination file.
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Syzbot reported this with the following trace:
Detalles técnicos trazas, registros y código del informe original
INFO: task kworker/u8:3:57 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:3 state:D stack:21600 pid:57 tgid:57 ppid:2 task_flags:0x4208160 flags:0x00080000
Workqueue: writeback wb_workfn (flush-btrfs-129)
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5402 [inline]
__schedule+0x16f9/0x5500 kernel/sched/core.c:7204
__schedule_loop kernel/sched/core.c:7283 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7298
wait_extent_bit fs/btrfs/extent-io-tree.c:905 [inline]
btrfs_lock_extent_bits+0x59c/0x700 fs/btrfs/extent-io-tree.c:2008
btrfs_lock_extent fs/btrfs/extent-io-tree.h:152 [inline]
btrfs_invalidate_folio+0x440/0xc00 fs/btrfs/inode.c:7718
extent_writepage fs/btrfs/extent_io.c:1848 [inline]
extent_write_cache_pages fs/btrfs/extent_io.c:2552 [inline]
btrfs_writepages+0x12f3/0x2410 fs/btrfs/extent_io.c:2684
do_writepages+0x32e/0x550 mm/page-writeback.c:2571
__writeback_single_inode+0x133/0x10e0 fs/fs-writeback.c:1764
writeback_sb_inodes+0x97f/0x1980 fs/fs-writeback.c:2056
wb_writeback+0x445/0xb00 fs/fs-writeback.c:2241
wb_do_writeback fs/fs-writeback.c:2388 [inline]
wb_workfn+0x3fd/0xf20 fs/fs-writeback.c:2428
process_one_work+0x98b/0x1630 kernel/workqueue.c:3318
process_scheduled_works kernel/workqueue.c:3401 [inline]
worker_thread+0xb49/0x1140 kernel/workqueue.c:3482
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
INFO: task syz.0.145:8523 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.145 state:D stack:22752 pid:8523 tgid:8522 ppid:5850 task_flags:0x400140 flags:0x00080002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5402 [inline]
__schedule+0x16f9/0x5500 kernel/sched/core.c:7204
__schedule_loop kernel/sched/core.c:7283 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7298
wb_wait_for_completion+0x3e8/0x790 fs/fs-writeback.c:227
__writeback_inodes_sb_nr+0x24c/0x2d0 fs/fs-writeback.c:2847
try_to_writeback_inodes_sb+0x9a/0xc0 fs/fs-writeback.c:2895
btrfs_start_delalloc_flush fs/btrfs/transaction.c:2182 [inline]
btrfs_commit_transaction+0x813/0x2fc0 fs/btrfs/transaction.c:2371
btrfs_sync_file+0xdf4/0x1230 fs/btrfs/file.c:1822
generic_write_sync include/linux/fs.h:2663 [inline]
btrfs_do_write_iter+0x6a9/0x840 fs/btrfs/file.c:1473
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x629/0xba0 fs/read_write.c:688
ksys_write+0x156/0x270 fs/read_write.c:740
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0x560 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5a0bdece59
RSP: 002b:00007f5a0b446028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f5a0c065fa0 RCX: 00007f5a0bdece59
RDX: 000000000000029f RSI: 0000200000
---truncated---CVSS
NVD no ha asignado puntuación CVSS a esta CVE (habitual desde el cambio de política de abril de 2026).
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.21%
- Percentil entre todas las CVEs puntuadas: 10
- Fecha de la puntuación: 6/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
Referencias
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-74318",
"cveTags": [],
"metrics": {},
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "05a5a7621ce66c142e081ffc24dd6ade6e912061",
"lessThan": "06283034cec0fa357cbd85784ef7d3f5b2ce0790",
"versionType": "git"
},
{
"status": "affected",
"version": "05a5a7621ce66c142e081ffc24dd6ade6e912061",
"lessThan": "2aa37c8ef1092c6f088e23a90bffefc672831c09",
"versionType": "git"
},
{
"status": "affected",
"version": "05a5a7621ce66c142e081ffc24dd6ade6e912061",
"lessThan": "ea3452726ccb6bcaa732f43cc57bb928eca3dd59",
"versionType": "git"
},
{
"status": "affected",
"version": "05a5a7621ce66c142e081ffc24dd6ade6e912061",
"lessThan": "532085d00eb54c074bdeae648b194765239f4d11",
"versionType": "git"
}
],
"programFiles": [
"fs/btrfs/reflink.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.7"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.7",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.12.97",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.40",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.5",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/btrfs/reflink.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-08-15T06:22:32.177",
"references": [
{
"url": "https://git.kernel.org/stable/c/06283034cec0fa357cbd85784ef7d3f5b2ce0790",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/2aa37c8ef1092c6f088e23a90bffefc672831c09",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/532085d00eb54c074bdeae648b194765239f4d11",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/ea3452726ccb6bcaa732f43cc57bb928eca3dd59",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix deadlock cloning inline extent when using flushoncommit\n\nIn commit b48c980b6a7e (\"btrfs: fix deadlock between reflink and\ntransaction commit when using flushoncommit\") a deadlock was fixed\nbetween reflinks and transaction commits when the fs is mounted with the\nflushoncommit option. This happened when we had to copy an inline extent's\ndata to the destination file. However the issue was fixed only for the\ncase where the destination offset is 0, it missed the case when the offset\nis greater than zero.\n\nFix this by ensuring we get i_size update whenever we copied an inline\nextent's data into the destination file.\n\nSyzbot reported this with the following trace:\n\n INFO: task kworker/u8:3:57 blocked for more than 143 seconds.\n Not tainted syzkaller #0\n \"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\" disables this message.\n task:kworker/u8:3 state:D stack:21600 pid:57 tgid:57 ppid:2 task_flags:0x4208160 flags:0x00080000\n Workqueue: writeback wb_workfn (flush-btrfs-129)\n Call Trace:\n <TASK>\n context_switch kernel/sched/core.c:5402 [inline]\n __schedule+0x16f9/0x5500 kernel/sched/core.c:7204\n __schedule_loop kernel/sched/core.c:7283 [inline]\n schedule+0x164/0x360 kernel/sched/core.c:7298\n wait_extent_bit fs/btrfs/extent-io-tree.c:905 [inline]\n btrfs_lock_extent_bits+0x59c/0x700 fs/btrfs/extent-io-tree.c:2008\n btrfs_lock_extent fs/btrfs/extent-io-tree.h:152 [inline]\n btrfs_invalidate_folio+0x440/0xc00 fs/btrfs/inode.c:7718\n extent_writepage fs/btrfs/extent_io.c:1848 [inline]\n extent_write_cache_pages fs/btrfs/extent_io.c:2552 [inline]\n btrfs_writepages+0x12f3/0x2410 fs/btrfs/extent_io.c:2684\n do_writepages+0x32e/0x550 mm/page-writeback.c:2571\n __writeback_single_inode+0x133/0x10e0 fs/fs-writeback.c:1764\n writeback_sb_inodes+0x97f/0x1980 fs/fs-writeback.c:2056\n wb_writeback+0x445/0xb00 fs/fs-writeback.c:2241\n wb_do_writeback fs/fs-writeback.c:2388 [inline]\n wb_workfn+0x3fd/0xf20 fs/fs-writeback.c:2428\n process_one_work+0x98b/0x1630 kernel/workqueue.c:3318\n process_scheduled_works kernel/workqueue.c:3401 [inline]\n worker_thread+0xb49/0x1140 kernel/workqueue.c:3482\n kthread+0x388/0x470 kernel/kthread.c:436\n ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158\n ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245\n </TASK>\n INFO: task syz.0.145:8523 blocked for more than 143 seconds.\n Not tainted syzkaller #0\n \"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\" disables this message.\n task:syz.0.145 state:D stack:22752 pid:8523 tgid:8522 ppid:5850 task_flags:0x400140 flags:0x00080002\n Call Trace:\n <TASK>\n context_switch kernel/sched/core.c:5402 [inline]\n __schedule+0x16f9/0x5500 kernel/sched/core.c:7204\n __schedule_loop kernel/sched/core.c:7283 [inline]\n schedule+0x164/0x360 kernel/sched/core.c:7298\n wb_wait_for_completion+0x3e8/0x790 fs/fs-writeback.c:227\n __writeback_inodes_sb_nr+0x24c/0x2d0 fs/fs-writeback.c:2847\n try_to_writeback_inodes_sb+0x9a/0xc0 fs/fs-writeback.c:2895\n btrfs_start_delalloc_flush fs/btrfs/transaction.c:2182 [inline]\n btrfs_commit_transaction+0x813/0x2fc0 fs/btrfs/transaction.c:2371\n btrfs_sync_file+0xdf4/0x1230 fs/btrfs/file.c:1822\n generic_write_sync include/linux/fs.h:2663 [inline]\n btrfs_do_write_iter+0x6a9/0x840 fs/btrfs/file.c:1473\n new_sync_write fs/read_write.c:595 [inline]\n vfs_write+0x629/0xba0 fs/read_write.c:688\n ksys_write+0x156/0x270 fs/read_write.c:740\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0x15f/0x560 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n RIP: 0033:0x7f5a0bdece59\n RSP: 002b:00007f5a0b446028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001\n RAX: ffffffffffffffda RBX: 00007f5a0c065fa0 RCX: 00007f5a0bdece59\n RDX: 000000000000029f RSI: 0000200000\n---truncated---"
}
],
"lastModified": "2026-08-17T06:19:26.207",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}