GHSA-W776-5FWP-835Q

Vulnerability from github – Published: 2026-03-25 12:30 – Updated: 2026-03-25 12:30
VLAI?
Details

In the Linux kernel, the following vulnerability has been resolved:

blktrace: fix __this_cpu_read/write in preemptible context

tracing_record_cmdline() internally uses __this_cpu_read() and __this_cpu_write() on the per-CPU variable trace_cmdline_save, and trace_save_cmdline() explicitly asserts preemption is disabled via lockdep_assert_preemption_disabled(). These operations are only safe when preemption is off, as they were designed to be called from the scheduler context (probe_wakeup_sched_switch() / probe_wakeup()).

__blk_add_trace() was calling tracing_record_cmdline(current) early in the blk_tracer path, before ring buffer reservation, from process context where preemption is fully enabled. This triggers the following using blktests/blktrace/002:

blktrace/002 (blktrace ftrace corruption with sysfs trace) [failed] runtime 0.367s ... 0.437s something found in dmesg: [ 81.211018] run blktests blktrace/002 at 2026-02-25 22:24:33 [ 81.239580] null_blk: disk nullb1 created [ 81.357294] BUG: using __this_cpu_read() in preemptible [00000000] code: dd/2516 [ 81.362842] caller is tracing_record_cmdline+0x10/0x40 [ 81.362872] CPU: 16 UID: 0 PID: 2516 Comm: dd Tainted: G N 7.0.0-rc1lblk+ #84 PREEMPT(full) [ 81.362877] Tainted: [N]=TEST [ 81.362878] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014 [ 81.362881] Call Trace: [ 81.362884] [ 81.362886] dump_stack_lvl+0x8d/0xb0 ... (See '/mnt/sda/blktests/results/nodev/blktrace/002.dmesg' for the entire message)

[ 81.211018] run blktests blktrace/002 at 2026-02-25 22:24:33 [ 81.239580] null_blk: disk nullb1 created [ 81.357294] BUG: using __this_cpu_read() in preemptible [00000000] code: dd/2516 [ 81.362842] caller is tracing_record_cmdline+0x10/0x40 [ 81.362872] CPU: 16 UID: 0 PID: 2516 Comm: dd Tainted: G N 7.0.0-rc1lblk+ #84 PREEMPT(full) [ 81.362877] Tainted: [N]=TEST [ 81.362878] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014 [ 81.362881] Call Trace: [ 81.362884] [ 81.362886] dump_stack_lvl+0x8d/0xb0 [ 81.362895] check_preemption_disabled+0xce/0xe0 [ 81.362902] tracing_record_cmdline+0x10/0x40 [ 81.362923] __blk_add_trace+0x307/0x5d0 [ 81.362934] ? lock_acquire+0xe0/0x300 [ 81.362940] ? iov_iter_extract_pages+0x101/0xa30 [ 81.362959] blk_add_trace_bio+0x106/0x1e0 [ 81.362968] submit_bio_noacct_nocheck+0x24b/0x3a0 [ 81.362979] ? lockdep_init_map_type+0x58/0x260 [ 81.362988] submit_bio_wait+0x56/0x90 [ 81.363009] __blkdev_direct_IO_simple+0x16c/0x250 [ 81.363026] ? __pfx_submit_bio_wait_endio+0x10/0x10 [ 81.363038] ? rcu_read_lock_any_held+0x73/0xa0 [ 81.363051] blkdev_read_iter+0xc1/0x140 [ 81.363059] vfs_read+0x20b/0x330 [ 81.363083] ksys_read+0x67/0xe0 [ 81.363090] do_syscall_64+0xbf/0xf00 [ 81.363102] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 81.363106] RIP: 0033:0x7f281906029d [ 81.363111] Code: 31 c0 e9 c6 fe ff ff 50 48 8d 3d 66 63 0a 00 e8 59 ff 01 00 66 0f 1f 84 00 00 00 00 00 80 3d 41 33 0e 00 00 74 17 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 5b c3 66 2e 0f 1f 84 00 00 00 00 00 48 83 ec [ 81.363113] RSP: 002b:00007ffca127dd48 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [ 81.363120] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f281906029d [ 81.363122] RDX: 0000000000001000 RSI: 0000559f8bfae000 RDI: 0000000000000000 [ 81.363123] RBP: 0000000000001000 R08: 0000002863a10a81 R09: 00007f281915f000 [ 81.363124] R10: 00007f2818f77b60 R11: 0000000000000246 R12: 0000559f8bfae000 [ 81.363126] R13: 0000000000000000 R14: 0000000000000000 R15: 000000000000000a [ 81.363142]

The same BUG fires from blk_add_trace_plug(), blk_add_trace_unplug(), and blk_add_trace_rq() paths as well.

The purpose of tracin ---truncated---

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{
  "affected": [],
  "aliases": [
    "CVE-2026-23374"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-03-25T11:16:37Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nblktrace: fix __this_cpu_read/write in preemptible context\n\ntracing_record_cmdline() internally uses __this_cpu_read() and\n__this_cpu_write() on the per-CPU variable trace_cmdline_save, and\ntrace_save_cmdline() explicitly asserts preemption is disabled via\nlockdep_assert_preemption_disabled(). These operations are only safe\nwhen preemption is off, as they were designed to be called from the\nscheduler context (probe_wakeup_sched_switch() / probe_wakeup()).\n\n__blk_add_trace() was calling tracing_record_cmdline(current) early in\nthe blk_tracer path, before ring buffer reservation, from process\ncontext where preemption is fully enabled. This triggers the following\nusing blktests/blktrace/002:\n\nblktrace/002 (blktrace ftrace corruption with sysfs trace)   [failed]\n    runtime  0.367s  ...  0.437s\n    something found in dmesg:\n    [   81.211018] run blktests blktrace/002 at 2026-02-25 22:24:33\n    [   81.239580] null_blk: disk nullb1 created\n    [   81.357294] BUG: using __this_cpu_read() in preemptible [00000000] code: dd/2516\n    [   81.362842] caller is tracing_record_cmdline+0x10/0x40\n    [   81.362872] CPU: 16 UID: 0 PID: 2516 Comm: dd Tainted: G                 N  7.0.0-rc1lblk+ #84 PREEMPT(full)\n    [   81.362877] Tainted: [N]=TEST\n    [   81.362878] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014\n    [   81.362881] Call Trace:\n    [   81.362884]  \u003cTASK\u003e\n    [   81.362886]  dump_stack_lvl+0x8d/0xb0\n    ...\n    (See \u0027/mnt/sda/blktests/results/nodev/blktrace/002.dmesg\u0027 for the entire message)\n\n[   81.211018] run blktests blktrace/002 at 2026-02-25 22:24:33\n[   81.239580] null_blk: disk nullb1 created\n[   81.357294] BUG: using __this_cpu_read() in preemptible [00000000] code: dd/2516\n[   81.362842] caller is tracing_record_cmdline+0x10/0x40\n[   81.362872] CPU: 16 UID: 0 PID: 2516 Comm: dd Tainted: G                 N  7.0.0-rc1lblk+ #84 PREEMPT(full)\n[   81.362877] Tainted: [N]=TEST\n[   81.362878] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014\n[   81.362881] Call Trace:\n[   81.362884]  \u003cTASK\u003e\n[   81.362886]  dump_stack_lvl+0x8d/0xb0\n[   81.362895]  check_preemption_disabled+0xce/0xe0\n[   81.362902]  tracing_record_cmdline+0x10/0x40\n[   81.362923]  __blk_add_trace+0x307/0x5d0\n[   81.362934]  ? lock_acquire+0xe0/0x300\n[   81.362940]  ? iov_iter_extract_pages+0x101/0xa30\n[   81.362959]  blk_add_trace_bio+0x106/0x1e0\n[   81.362968]  submit_bio_noacct_nocheck+0x24b/0x3a0\n[   81.362979]  ? lockdep_init_map_type+0x58/0x260\n[   81.362988]  submit_bio_wait+0x56/0x90\n[   81.363009]  __blkdev_direct_IO_simple+0x16c/0x250\n[   81.363026]  ? __pfx_submit_bio_wait_endio+0x10/0x10\n[   81.363038]  ? rcu_read_lock_any_held+0x73/0xa0\n[   81.363051]  blkdev_read_iter+0xc1/0x140\n[   81.363059]  vfs_read+0x20b/0x330\n[   81.363083]  ksys_read+0x67/0xe0\n[   81.363090]  do_syscall_64+0xbf/0xf00\n[   81.363102]  entry_SYSCALL_64_after_hwframe+0x76/0x7e\n[   81.363106] RIP: 0033:0x7f281906029d\n[   81.363111] Code: 31 c0 e9 c6 fe ff ff 50 48 8d 3d 66 63 0a 00 e8 59 ff 01 00 66 0f 1f 84 00 00 00 00 00 80 3d 41 33 0e 00 00 74 17 31 c0 0f 05 \u003c48\u003e 3d 00 f0 ff ff 77 5b c3 66 2e 0f 1f 84 00 00 00 00 00 48 83 ec\n[   81.363113] RSP: 002b:00007ffca127dd48 EFLAGS: 00000246 ORIG_RAX: 0000000000000000\n[   81.363120] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f281906029d\n[   81.363122] RDX: 0000000000001000 RSI: 0000559f8bfae000 RDI: 0000000000000000\n[   81.363123] RBP: 0000000000001000 R08: 0000002863a10a81 R09: 00007f281915f000\n[   81.363124] R10: 00007f2818f77b60 R11: 0000000000000246 R12: 0000559f8bfae000\n[   81.363126] R13: 0000000000000000 R14: 0000000000000000 R15: 000000000000000a\n[   81.363142]  \u003c/TASK\u003e\n\nThe same BUG fires from blk_add_trace_plug(), blk_add_trace_unplug(),\nand blk_add_trace_rq() paths as well.\n\nThe purpose of tracin\n---truncated---",
  "id": "GHSA-w776-5fwp-835q",
  "modified": "2026-03-25T12:30:24Z",
  "published": "2026-03-25T12:30:24Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23374"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/59efa088752b1c380a0475974679850cc8aef907"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/da46b5dfef48658d03347cda21532bcdbb521e67"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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