If xace hardware reports a bad version number, the error handling code
in ace_setup() calls put_disk(), followed by queue cleanup. However, since
the disk data structure has the queue pointer set, put_disk() also
cleans and releases the queue. This results in blk_cleanup_queue()
accessing an already released data structure, which in turn may result
in a crash such as the following.
[ 10.681671] BUG: Kernel NULL pointer dereference at 0x00000040
[ 10.681826] Faulting instruction address: 0xc0431480
[ 10.682072] Oops: Kernel access of bad area, sig: 11 [#1]
[ 10.682251] BE PAGE_SIZE=4K PREEMPT Xilinx Virtex440
[ 10.682387] Modules linked in:
[ 10.682528] CPU: 0 PID: 1 Comm: swapper Tainted: G W 5.0.0-rc6-next-
20190218+ #2
[ 10.682733] NIP:
c0431480 LR:
c043147c CTR:
c0422ad8
[ 10.682863] REGS:
cf82fbe0 TRAP: 0300 Tainted: G W (5.0.0-rc6-next-
20190218+)
[ 10.683065] MSR:
00029000 <CE,EE,ME> CR:
22000222 XER:
00000000
[ 10.683236] DEAR:
00000040 ESR:
00000000
[ 10.683236] GPR00:
c043147c cf82fc90 cf82ccc0 00000000 00000000 00000000 00000002 00000000
[ 10.683236] GPR08:
00000000 00000000 c04310bc 00000000 22000222 00000000 c0002c54 00000000
[ 10.683236] GPR16:
00000000 00000001 c09aa39c c09021b0 c09021dc 00000007 c0a68c08 00000000
[ 10.683236] GPR24:
00000001 ced6d400 ced6dcf0 c0815d9c 00000000 00000000 00000000 cedf0800
[ 10.684331] NIP [
c0431480] blk_mq_run_hw_queue+0x28/0x114
[ 10.684473] LR [
c043147c] blk_mq_run_hw_queue+0x24/0x114
[ 10.684602] Call Trace:
[ 10.684671] [
cf82fc90] [
c043147c] blk_mq_run_hw_queue+0x24/0x114 (unreliable)
[ 10.684854] [
cf82fcc0] [
c04315bc] blk_mq_run_hw_queues+0x50/0x7c
[ 10.685002] [
cf82fce0] [
c0422b24] blk_set_queue_dying+0x30/0x68
[ 10.685154] [
cf82fcf0] [
c0423ec0] blk_cleanup_queue+0x34/0x14c
[ 10.685306] [
cf82fd10] [
c054d73c] ace_probe+0x3dc/0x508
[ 10.685445] [
cf82fd50] [
c052d740] platform_drv_probe+0x4c/0xb8
[ 10.685592] [
cf82fd70] [
c052abb0] really_probe+0x20c/0x32c
[ 10.685728] [
cf82fda0] [
c052ae58] driver_probe_device+0x68/0x464
[ 10.685877] [
cf82fdc0] [
c052b500] device_driver_attach+0xb4/0xe4
[ 10.686024] [
cf82fde0] [
c052b5dc] __driver_attach+0xac/0xfc
[ 10.686161] [
cf82fe00] [
c0528428] bus_for_each_dev+0x80/0xc0
[ 10.686314] [
cf82fe30] [
c0529b3c] bus_add_driver+0x144/0x234
[ 10.686457] [
cf82fe50] [
c052c46c] driver_register+0x88/0x15c
[ 10.686610] [
cf82fe60] [
c09de288] ace_init+0x4c/0xac
[ 10.686742] [
cf82fe80] [
c0002730] do_one_initcall+0xac/0x330
[ 10.686888] [
cf82fee0] [
c09aafd0] kernel_init_freeable+0x34c/0x478
[ 10.687043] [
cf82ff30] [
c0002c6c] kernel_init+0x18/0x114
[ 10.687188] [
cf82ff40] [
c000f2f0] ret_from_kernel_thread+0x14/0x1c
[ 10.687349] Instruction dump:
[ 10.687435]
3863ffd4 4bfffd70 9421ffd0 7c0802a6 93c10028 7c9e2378 93e1002c 38810008
[ 10.687637]
7c7f1b78 90010034 4bfffc25 813f008c <
81290040>
75290100 4182002c 80810008
[ 10.688056] ---[ end trace
13c9ff51d41b9d40 ]---
Fix the problem by setting the disk queue pointer to NULL before calling
put_disk(). A more comprehensive fix might be to rearrange the code
to check the hardware version before initializing data structures,
but I don't know if this would have undesirable side effects, and
it would increase the complexity of backporting the fix to older kernels.
Fixes: 74489a91dd43a ("Add support for Xilinx SystemACE CompactFlash interface")
Acked-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
projects / openwrt / staging / blogic.git / commitdiff