In the Linux kernel, the following vulnerability has been resolved:
rbd: fix null-ptr-deref when device_add_disk() fails
do_rbd_add() publishes the device with device_add() before calling
device_add_disk(). If device_add_disk() fails after device_add()
succeeds, the error path calls rbd_free_disk() directly and then later
falls through to rbd_dev_device_release(), which calls rbd_free_disk()
again. This double teardown can leave blk-mq cleanup operating on
invalid state and trigger a null-ptr-deref in
__blk_mq_free_map_and_rqs(), reached from blk_mq_free_tag_set().
Fix this by following the normal remove ordering: call device_del()
before rbd_dev_device_release() when device_add_disk() fails after
device_add(). That keeps the teardown sequence consistent and avoids
re-entering disk cleanup through the wrong path.
The bug was first flagged by an experimental analysis tool we are
developing for kernel memory-management bugs while analyzing
v6.13-rc1. The tool is still under development and is not yet publicly
available.
We reproduced the bug on v7.0 with a real Ceph backend and a QEMU x86_64
guest booted with KASAN and CONFIG_FAILSLAB enabled. The reproducer
confines failslab injections to the __add_disk() range and injects
fail-nth while mapping an RBD image through
/sys/bus/rbd/add_single_major.
On the unpatched kernel, fail-nth=4 reliably triggered the fault:
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 UID: 0 PID: 273 Comm: bash Not tainted 7.0.0-01247-gd60bc1401583 #6 PREEMPT(lazy)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014
RIP: 0010:__blk_mq_free_map_and_rqs+0x8c/0x240
Code: 00 00 48 8b 6b 60 41 89 f4 49 c1 e4 03 4c 01 e5 45 85 ed 0f 85 0a 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 e9 48 c1 e9 03 <80> 3c 01 00 0f 85 31 01 00 00 4c 8b 6d 00 4d 85 ed 0f 84 e2 00 00
RSP: 0018:ff1100000ab0fac8 EFLAGS: 00000246
RAX: dffffc0000000000 RBX: ff1100000c4806a0 RCX: 0000000000000000
RDX: 0000000000000002 RSI: 0000000000000000 RDI: ff1100000c4806f4
RBP: 0000000000000000 R08: 0000000000000001 R09: ffe21c000189001b
R10: ff1100000c4800df R11: ff1100006cf37be0 R12: 0000000000000000
R13: 0000000000000000 R14: ff1100000c480700 R15: ff1100000c480004
FS: 00007f0fbe8fe740(0000) GS:ff110000e5851000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe53473b2e0 CR3: 0000000012eef000 CR4: 00000000007516f0
PKRU: 55555554
Call Trace:
<TASK>
blk_mq_free_tag_set+0x77/0x460
do_rbd_add+0x1446/0x2b80
? __pfx_do_rbd_add+0x10/0x10
? lock_acquire+0x18c/0x300
? find_held_lock+0x2b/0x80
? sysfs_file_kobj+0xb6/0x1b0
? __pfx_sysfs_kf_write+0x10/0x10
kernfs_fop_write_iter+0x2f4/0x4a0
vfs_write+0x98e/0x1000
? expand_files+0x51f/0x850
? __pfx_vfs_write+0x10/0x10
ksys_write+0xf2/0x1d0
? __pfx_ksys_write+0x10/0x10
do_syscall_64+0x115/0x690
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0fbea15907
Code: 10 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24
RSP: 002b:00007ffe22346ea8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000058 RCX: 00007f0fbea15907
RDX: 0000000000000058 RSI: 0000563ace6c0ef0 RDI: 0000000000000001
RBP: 0000563ace6c0ef0 R08: 0000563ace6c0ef0 R09: 6b6435726d694141
R10: 5250337279762f78 R11: 0000000000000246 R12: 0000000000000058
R13: 00007f0fbeb1c780 R14: ff1100000c480700 R15: ff1100000c480004
</TASK>
With this fix applied, rerunning the reproducer over fail-nth=1..256
yields no KASAN reports.
[ idryomov: rename err_out_device_del -> err_out_device ]
rbd: fix null-ptr-deref when device_add_disk() fails
do_rbd_add() publishes the device with device_add() before calling
device_add_disk(). If device_add_disk() fails after device_add()
succeeds, the error path calls rbd_free_disk() directly and then later
falls through to rbd_dev_device_release(), which calls rbd_free_disk()
again. This double teardown can leave blk-mq cleanup operating on
invalid state and trigger a null-ptr-deref in
__blk_mq_free_map_and_rqs(), reached from blk_mq_free_tag_set().
Fix this by following the normal remove ordering: call device_del()
before rbd_dev_device_release() when device_add_disk() fails after
device_add(). That keeps the teardown sequence consistent and avoids
re-entering disk cleanup through the wrong path.
The bug was first flagged by an experimental analysis tool we are
developing for kernel memory-management bugs while analyzing
v6.13-rc1. The tool is still under development and is not yet publicly
available.
We reproduced the bug on v7.0 with a real Ceph backend and a QEMU x86_64
guest booted with KASAN and CONFIG_FAILSLAB enabled. The reproducer
confines failslab injections to the __add_disk() range and injects
fail-nth while mapping an RBD image through
/sys/bus/rbd/add_single_major.
On the unpatched kernel, fail-nth=4 reliably triggered the fault:
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 UID: 0 PID: 273 Comm: bash Not tainted 7.0.0-01247-gd60bc1401583 #6 PREEMPT(lazy)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014
RIP: 0010:__blk_mq_free_map_and_rqs+0x8c/0x240
Code: 00 00 48 8b 6b 60 41 89 f4 49 c1 e4 03 4c 01 e5 45 85 ed 0f 85 0a 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 e9 48 c1 e9 03 <80> 3c 01 00 0f 85 31 01 00 00 4c 8b 6d 00 4d 85 ed 0f 84 e2 00 00
RSP: 0018:ff1100000ab0fac8 EFLAGS: 00000246
RAX: dffffc0000000000 RBX: ff1100000c4806a0 RCX: 0000000000000000
RDX: 0000000000000002 RSI: 0000000000000000 RDI: ff1100000c4806f4
RBP: 0000000000000000 R08: 0000000000000001 R09: ffe21c000189001b
R10: ff1100000c4800df R11: ff1100006cf37be0 R12: 0000000000000000
R13: 0000000000000000 R14: ff1100000c480700 R15: ff1100000c480004
FS: 00007f0fbe8fe740(0000) GS:ff110000e5851000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe53473b2e0 CR3: 0000000012eef000 CR4: 00000000007516f0
PKRU: 55555554
Call Trace:
<TASK>
blk_mq_free_tag_set+0x77/0x460
do_rbd_add+0x1446/0x2b80
? __pfx_do_rbd_add+0x10/0x10
? lock_acquire+0x18c/0x300
? find_held_lock+0x2b/0x80
? sysfs_file_kobj+0xb6/0x1b0
? __pfx_sysfs_kf_write+0x10/0x10
kernfs_fop_write_iter+0x2f4/0x4a0
vfs_write+0x98e/0x1000
? expand_files+0x51f/0x850
? __pfx_vfs_write+0x10/0x10
ksys_write+0xf2/0x1d0
? __pfx_ksys_write+0x10/0x10
do_syscall_64+0x115/0x690
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0fbea15907
Code: 10 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24
RSP: 002b:00007ffe22346ea8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000058 RCX: 00007f0fbea15907
RDX: 0000000000000058 RSI: 0000563ace6c0ef0 RDI: 0000000000000001
RBP: 0000563ace6c0ef0 R08: 0000563ace6c0ef0 R09: 6b6435726d694141
R10: 5250337279762f78 R11: 0000000000000246 R12: 0000000000000058
R13: 00007f0fbeb1c780 R14: ff1100000c480700 R15: ff1100000c480004
</TASK>
With this fix applied, rerunning the reproducer over fail-nth=1..256
yields no KASAN reports.
[ idryomov: rename err_out_device_del -> err_out_device ]
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
||||||||||||||||||||||||
| Linux | Linux | affected |
|
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Advisories
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Fixes
Solution
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Workaround
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References
History
Wed, 27 May 2026 14:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: rbd: fix null-ptr-deref when device_add_disk() fails do_rbd_add() publishes the device with device_add() before calling device_add_disk(). If device_add_disk() fails after device_add() succeeds, the error path calls rbd_free_disk() directly and then later falls through to rbd_dev_device_release(), which calls rbd_free_disk() again. This double teardown can leave blk-mq cleanup operating on invalid state and trigger a null-ptr-deref in __blk_mq_free_map_and_rqs(), reached from blk_mq_free_tag_set(). Fix this by following the normal remove ordering: call device_del() before rbd_dev_device_release() when device_add_disk() fails after device_add(). That keeps the teardown sequence consistent and avoids re-entering disk cleanup through the wrong path. The bug was first flagged by an experimental analysis tool we are developing for kernel memory-management bugs while analyzing v6.13-rc1. The tool is still under development and is not yet publicly available. We reproduced the bug on v7.0 with a real Ceph backend and a QEMU x86_64 guest booted with KASAN and CONFIG_FAILSLAB enabled. The reproducer confines failslab injections to the __add_disk() range and injects fail-nth while mapping an RBD image through /sys/bus/rbd/add_single_major. On the unpatched kernel, fail-nth=4 reliably triggered the fault: Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 0 UID: 0 PID: 273 Comm: bash Not tainted 7.0.0-01247-gd60bc1401583 #6 PREEMPT(lazy) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014 RIP: 0010:__blk_mq_free_map_and_rqs+0x8c/0x240 Code: 00 00 48 8b 6b 60 41 89 f4 49 c1 e4 03 4c 01 e5 45 85 ed 0f 85 0a 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 e9 48 c1 e9 03 <80> 3c 01 00 0f 85 31 01 00 00 4c 8b 6d 00 4d 85 ed 0f 84 e2 00 00 RSP: 0018:ff1100000ab0fac8 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: ff1100000c4806a0 RCX: 0000000000000000 RDX: 0000000000000002 RSI: 0000000000000000 RDI: ff1100000c4806f4 RBP: 0000000000000000 R08: 0000000000000001 R09: ffe21c000189001b R10: ff1100000c4800df R11: ff1100006cf37be0 R12: 0000000000000000 R13: 0000000000000000 R14: ff1100000c480700 R15: ff1100000c480004 FS: 00007f0fbe8fe740(0000) GS:ff110000e5851000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe53473b2e0 CR3: 0000000012eef000 CR4: 00000000007516f0 PKRU: 55555554 Call Trace: <TASK> blk_mq_free_tag_set+0x77/0x460 do_rbd_add+0x1446/0x2b80 ? __pfx_do_rbd_add+0x10/0x10 ? lock_acquire+0x18c/0x300 ? find_held_lock+0x2b/0x80 ? sysfs_file_kobj+0xb6/0x1b0 ? __pfx_sysfs_kf_write+0x10/0x10 kernfs_fop_write_iter+0x2f4/0x4a0 vfs_write+0x98e/0x1000 ? expand_files+0x51f/0x850 ? __pfx_vfs_write+0x10/0x10 ksys_write+0xf2/0x1d0 ? __pfx_ksys_write+0x10/0x10 do_syscall_64+0x115/0x690 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0fbea15907 Code: 10 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24 RSP: 002b:00007ffe22346ea8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000058 RCX: 00007f0fbea15907 RDX: 0000000000000058 RSI: 0000563ace6c0ef0 RDI: 0000000000000001 RBP: 0000563ace6c0ef0 R08: 0000563ace6c0ef0 R09: 6b6435726d694141 R10: 5250337279762f78 R11: 0000000000000246 R12: 0000000000000058 R13: 00007f0fbeb1c780 R14: ff1100000c480700 R15: ff1100000c480004 </TASK> With this fix applied, rerunning the reproducer over fail-nth=1..256 yields no KASAN reports. [ idryomov: rename err_out_device_del -> err_out_device ] | |
| Title | rbd: fix null-ptr-deref when device_add_disk() fails | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-27T12:58:13.903Z
Reserved: 2026-05-13T15:03:33.096Z
Link: CVE-2026-46079
Vulnrichment
No data.
NVD
Status : Awaiting Analysis
Published: 2026-05-27T14:17:29.253
Modified: 2026-05-27T14:48:03.013
Link: CVE-2026-46079
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.