CVE-2021-47552
blk-mq: cancel blk-mq dispatch work in both blk_cleanup_queue and disk_release()
Severity Score
Exploit Likelihood
Affected Versions
Public Exploits
0Exploited in Wild
-Decision
Descriptions
In the Linux kernel, the following vulnerability has been resolved:
blk-mq: cancel blk-mq dispatch work in both blk_cleanup_queue and disk_release()
For avoiding to slow down queue destroy, we don't call
blk_mq_quiesce_queue() in blk_cleanup_queue(), instead of delaying to
cancel dispatch work in blk_release_queue().
However, this way has caused kernel oops[1], reported by Changhui. The log
shows that scsi_device can be freed before running blk_release_queue(),
which is expected too since scsi_device is released after the scsi disk
is closed and the scsi_device is removed.
Fixes the issue by canceling blk-mq dispatch work in both blk_cleanup_queue()
and disk_release():
1) when disk_release() is run, the disk has been closed, and any sync
dispatch activities have been done, so canceling dispatch work is enough to
quiesce filesystem I/O dispatch activity.
2) in blk_cleanup_queue(), we only focus on passthrough request, and
passthrough request is always explicitly allocated & freed by
its caller, so once queue is frozen, all sync dispatch activity
for passthrough request has been done, then it is enough to just cancel
dispatch work for avoiding any dispatch activity.
[1] kernel panic log
[12622.769416] BUG: kernel NULL pointer dereference, address: 0000000000000300
[12622.777186] #PF: supervisor read access in kernel mode
[12622.782918] #PF: error_code(0x0000) - not-present page
[12622.788649] PGD 0 P4D 0
[12622.791474] Oops: 0000 [#1] PREEMPT SMP PTI
[12622.796138] CPU: 10 PID: 744 Comm: kworker/10:1H Kdump: loaded Not tainted 5.15.0+ #1
[12622.804877] Hardware name: Dell Inc. PowerEdge R730/0H21J3, BIOS 1.5.4 10/002/2015
[12622.813321] Workqueue: kblockd blk_mq_run_work_fn
[12622.818572] RIP: 0010:sbitmap_get+0x75/0x190
[12622.823336] Code: 85 80 00 00 00 41 8b 57 08 85 d2 0f 84 b1 00 00 00 45 31 e4 48 63 cd 48 8d 1c 49 48 c1 e3 06 49 03 5f 10 4c 8d 6b 40 83 f0 01 <48> 8b 33 44 89 f2 4c 89 ef 0f b6 c8 e8 fa f3 ff ff 83 f8 ff 75 58
[12622.844290] RSP: 0018:ffffb00a446dbd40 EFLAGS: 00010202
[12622.850120] RAX: 0000000000000001 RBX: 0000000000000300 RCX: 0000000000000004
[12622.858082] RDX: 0000000000000006 RSI: 0000000000000082 RDI: ffffa0b7a2dfe030
[12622.866042] RBP: 0000000000000004 R08: 0000000000000001 R09: ffffa0b742721334
[12622.874003] R10: 0000000000000008 R11: 0000000000000008 R12: 0000000000000000
[12622.881964] R13: 0000000000000340 R14: 0000000000000000 R15: ffffa0b7a2dfe030
[12622.889926] FS: 0000000000000000(0000) GS:ffffa0baafb40000(0000) knlGS:0000000000000000
[12622.898956] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[12622.905367] CR2: 0000000000000300 CR3: 0000000641210001 CR4: 00000000001706e0
[12622.913328] Call Trace:
[12622.916055] <TASK>
[12622.918394] scsi_mq_get_budget+0x1a/0x110
[12622.922969] __blk_mq_do_dispatch_sched+0x1d4/0x320
[12622.928404] ? pick_next_task_fair+0x39/0x390
[12622.933268] __blk_mq_sched_dispatch_requests+0xf4/0x140
[12622.939194] blk_mq_sched_dispatch_requests+0x30/0x60
[12622.944829] __blk_mq_run_hw_queue+0x30/0xa0
[12622.949593] process_one_work+0x1e8/0x3c0
[12622.954059] worker_thread+0x50/0x3b0
[12622.958144] ? rescuer_thread+0x370/0x370
[12622.962616] kthread+0x158/0x180
[12622.966218] ? set_kthread_struct+0x40/0x40
[12622.970884] ret_from_fork+0x22/0x30
[12622.974875] </TASK>
[12622.977309] Modules linked in: scsi_debug rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace fscache netfs sunrpc dm_multipath intel_rapl_msr intel_rapl_common dell_wmi_descriptor sb_edac rfkill video x86_pkg_temp_thermal intel_powerclamp dcdbas coretemp kvm_intel kvm mgag200 irqbypass i2c_algo_bit rapl drm_kms_helper ipmi_ssif intel_cstate intel_uncore syscopyarea sysfillrect sysimgblt fb_sys_fops pcspkr cec mei_me lpc_ich mei ipmi_si ipmi_devintf ipmi_msghandler acpi_power_meter drm fuse xfs libcrc32c sr_mod cdrom sd_mod t10_pi sg ixgbe ahci libahci crct10dif_pclmul crc32_pclmul crc32c_intel libata megaraid_sas ghash_clmulni_intel tg3 wdat_w
---truncated---
En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: blk-mq: cancela el trabajo de envío de blk-mq tanto en blk_cleanup_queue como en disk_release() Para evitar ralentizar la destrucción de la cola, no llamamos a blk_mq_quiesce_queue() en blk_cleanup_queue(). en lugar de retrasar la cancelación del trabajo de envío en blk_release_queue(). Sin embargo, esta forma ha provocado errores en el kernel[1], según informó Changhui. El registro muestra que scsi_device se puede liberar antes de ejecutar blk_release_queue(), lo cual también se espera ya que scsi_device se libera después de que se cierra el disco scsi y se elimina scsi_device. Soluciona el problema cancelando el trabajo de envío de blk-mq tanto en blk_cleanup_queue() como en disk_release(): 1) cuando se ejecuta disk_release(), el disco se ha cerrado y se han realizado todas las actividades de envío de sincronización, por lo que cancelar el trabajo de envío es suficiente para inmovilizar la actividad de envío de E/S del sistema de archivos. 2) en blk_cleanup_queue(), solo nos centramos en la solicitud de paso a través, y la persona que llama siempre asigna y libera explícitamente la solicitud de paso a través, por lo que una vez que la cola se congela, se ha realizado toda la actividad de envío de sincronización para la solicitud de paso a través, entonces es suficiente con simplemente cancelar el trabajo de despacho para evitar cualquier actividad de despacho. [1] registro de pánico del kernel [12622.769416] ERROR: desreferencia del puntero NULL del kernel, dirección: 0000000000000300 [12622.777186] #PF: acceso de lectura del supervisor en modo kernel [12622.782918] #PF: código de error (0x0000) - página no presente [12622.788649] re 0 P4D 0 [12622.791474] Ups: 0000 [#1] PREEMPT SMP PTI [12622.796138] CPU: 10 PID: 744 Comm: kworker/10:1H Kdump: cargado No contaminado 5.15.0+ #1 [12622.804877] Nombre de hardware: Dell Inc. PowerEdge R730/0H21J3, BIOS 1.5.4 10/002/2015 [12622.813321] Cola de trabajo: kblockd blk_mq_run_work_fn [12622.818572] RIP: 0010:sbitmap_get+0x75/0x190 [12622.823336] Código: 85 80 00 00 00 41 8b 57 08 85 d2 0f 84 b1 00 00 00 45 31 e4 48 63 cd 48 8d 1c 49 48 c1 e3 06 49 03 5f 10 4c 8d 6b 40 83 f0 01 <48> 8b 33 44 89 f2 4c 89 ef 0f b6 c8 e 8 fa f3 ff ff 83 f8 ff 75 58 [12622.844290] RSP: 0018:ffffb00a446dbd40 EFLAGS: 00010202 [12622.850120] RAX: 00000000000000001 RBX: 0000000000000300 0000000000000004 [12622.858082] RDX: 0000000000000006 RSI: 0000000000000082 RDI: ffffa0b7a2dfe030 [12622.866042] RBP: 0000000000000004 8: 0000000000000001 R09: ffffa0b742721334 [12622.874003] R10: 0000000000000008 R11: 0000000000000008 R12: 00000000000000000 [12622.881964] R13: 0000340 R14: 0000000000000000 R15: ffffa0b7a2dfe030 [12622.889926] FS: 0000000000000000(0000) GS:ffffa0baafb40000(0000) knlGS:000000000000000 00 [12622.898956] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [12622.905367] CR2: 0000000000000300 CR3: 0000000641210001 CR4: 00000000001706e0 [12622.913 328] Seguimiento de llamadas: [12622.916055] [12622.918394] scsi_mq_get_budget+0x1a/0x110 [12622.922969] __blk_mq_do_dispatch_sched+0x1d4/0x320 [12622.928404] ? pick_next_task_fair+0x39/0x390 [12622.933268] __blk_mq_sched_dispatch_requests+0xf4/0x140 [12622.939194] blk_mq_sched_dispatch_requests+0x30/0x60 [12622.944829] q_run_hw_queue+0x30/0xa0 [12622.949593] proceso_one_work+0x1e8/0x3c0 [12622.954059] trabajador_thread+0x50/0x3b0 [12622.958144] ? hilo_rescate+0x370/0x370 [12622.962616] kthread+0x158/0x180 [12622.966218] ? set_kthread_struct+0x40/0x40 [12622.970884] ret_from_fork+0x22/0x30 [12622.974875] [12622.977309] Módulos vinculados en: scsi_debug rpcsec_gss_krb5 auth_rpcgss nfsv4 solucionador nfs lockd gracia fscache netfs sunrpc dm_multipath intel_rapl_msr intel_rapl_common dell_wmi_descriptor sb_edac rfkill video x86_pkg_temp_thermal intel_powerclamp dcdbas coretemp kvm_intel kvm mgag200 irqbypass i2c_algo_bit rapl drm_kms_helper ipmi_ssif intel_cstate intel_uncore syscopyarea ---truncado---
CVSS Scores
SSVC
- Decision:Track
Timeline
- 2024-05-24 CVE Reserved
- 2024-05-24 CVE Published
- 2024-05-25 EPSS Updated
- 2024-08-04 CVE Updated
- ---------- Exploited in Wild
- ---------- KEV Due Date
- ---------- First Exploit
CWE
CAPEC
References (2)
| URL | Tag | Source |
|---|
| URL | Date | SRC |
|---|
| URL | Date | SRC |
|---|---|---|
| https://git.kernel.org/stable/c/e03513f58919d9e2bc6df765ca2c9da863d03d90 | 2021-12-01 | |
| https://git.kernel.org/stable/c/2a19b28f7929866e1cec92a3619f4de9f2d20005 | 2021-11-16 |
| URL | Date | SRC |
|---|
Affected Vendors, Products, and Versions
| Vendor | Product | Version | Other | Status | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Vendor | Product | Version | Other | Status | <-- --> | Vendor | Product | Version | Other | Status |
| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | < 5.15.6 Search vendor "Linux" for product "Linux Kernel" and version " < 5.15.6" | en |
Affected
| ||||||
| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | < 5.16 Search vendor "Linux" for product "Linux Kernel" and version " < 5.16" | en |
Affected
| ||||||