d1fef92e41
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 ]
Cc: stable@vger.kernel.org
Fixes:
|
||
|---|---|---|
| .. | ||
| accel | ||
| accessibility | ||
| acpi | ||
| amba | ||
| android | ||
| ata | ||
| atm | ||
| auxdisplay | ||
| base | ||
| bcma | ||
| block | ||
| bluetooth | ||
| bus | ||
| cache | ||
| cdrom | ||
| cdx | ||
| char | ||
| clk | ||
| clocksource | ||
| comedi | ||
| connector | ||
| counter | ||
| cpufreq | ||
| cpuidle | ||
| crypto | ||
| cxl | ||
| dax | ||
| dca | ||
| devfreq | ||
| dibs | ||
| dio | ||
| dma | ||
| dma-buf | ||
| dpll | ||
| edac | ||
| eisa | ||
| extcon | ||
| firewire | ||
| firmware | ||
| fpga | ||
| fsi | ||
| fwctl | ||
| gnss | ||
| gpib | ||
| gpio | ||
| gpu | ||
| greybus | ||
| hid | ||
| hsi | ||
| hte | ||
| hv | ||
| hwmon | ||
| hwspinlock | ||
| hwtracing | ||
| i2c | ||
| i3c | ||
| idle | ||
| iio | ||
| infiniband | ||
| input | ||
| interconnect | ||
| iommu | ||
| ipack | ||
| irqchip | ||
| isdn | ||
| leds | ||
| macintosh | ||
| mailbox | ||
| mcb | ||
| md | ||
| media | ||
| memory | ||
| memstick | ||
| message | ||
| mfd | ||
| misc | ||
| mmc | ||
| most | ||
| mtd | ||
| mux | ||
| net | ||
| nfc | ||
| ntb | ||
| nubus | ||
| nvdimm | ||
| nvme | ||
| nvmem | ||
| of | ||
| opp | ||
| parisc | ||
| parport | ||
| pci | ||
| pcmcia | ||
| peci | ||
| perf | ||
| phy | ||
| pinctrl | ||
| platform | ||
| pmdomain | ||
| pnp | ||
| power | ||
| powercap | ||
| pps | ||
| ps3 | ||
| ptp | ||
| pwm | ||
| rapidio | ||
| ras | ||
| regulator | ||
| remoteproc | ||
| resctrl | ||
| reset | ||
| rpmsg | ||
| rtc | ||
| s390 | ||
| sbus | ||
| scsi | ||
| sh | ||
| siox | ||
| slimbus | ||
| soc | ||
| soundwire | ||
| spi | ||
| spmi | ||
| ssb | ||
| staging | ||
| target | ||
| tc | ||
| tee | ||
| thermal | ||
| thunderbolt | ||
| tty | ||
| ufs | ||
| uio | ||
| usb | ||
| vdpa | ||
| vfio | ||
| vhost | ||
| video | ||
| virt | ||
| virtio | ||
| w1 | ||
| watchdog | ||
| xen | ||
| zorro | ||
| Kconfig | ||
| Makefile | ||