CONFIG_MTD_UBI_DEBUG_DISABLE_BGT=y corrupts slab?

Quoted 34 lines

UBIFS DBG (pid 172): mount_ubifs: commit number: 0
UBI DBG (pid 172): ubi_leb_read: read 160 bytes from LEB 2:11:0 UBI DBG (pid 172): ubi_io_read: read 160 bytes from PEB 13:4096 UBI DBG (pid 172): ubi_close_volume: close volume 2, mode 1

Unable to handle kernel paging request at virtual address ffffffff
pgd = c0004000
[ffffffff] *pgd=00002031, *pte=00000000, *ppte=00000000
Internal error: Oops: 817 [#1]
CPU: 0    Not tainted  (2.6.25-00101-gb6922fa-dirty #140)
PC is at free_block+0x84/0x158
LR is at 0xc5c02220
pc : [<c007c480>]    lr : [<c5c02220>]    psr: 00000093

sp : c5c23ef8 ip : c5f52000 fp : c5c23f24
r10: 00200200 r9 : 00100100 r8 : 00000018
r7 : c5c00300 r6 : 00000000 r5 : c5c05410 r4 : c5c00300 r3 : ffffffff r2 : ffffffff r1 : 00000000 r0 : c5f520a0
Flags: nzcv IRQs off FIQs on Mode SVC_32 ISA ARM Segment kernel
Control: 00003137 Table: 0555c000 DAC: 00000017
Process events/0 (pid: 4, stack limit = 0xc5c22268)

Stack: (0xc5c23ef8 to 0xc5c24000)

3ee0: c5c23f2c c5c05410
3f00: 00000018 c5c05400 c5c00300 c02db9f8 c0304cb4 00000005 c5c23f44 c5c23f28 3f20: c007c5fc c007c408 c5c02220 c5c00300 00000000 c0304cc0 c5c23f7c c5c23f48 3f40: c007d638 c007c560 00000000 c5411080 c5c23f9c c5c019e0 c5c22000 c007d5e0 3f60: 00000000 00000000 00000000 00000000 c5c23f9c c5c23f80 c0048a24 c007d5ec 3f80: c5c019e8 c5c22000 c5c019e0 c5c23fa4 c5c23fd4 c5c23fa0 c00494e8 c0048974 3fa0: c5c13260 00000000 c5c13000 c004c5e0 c5c23fb0 c5c23fb0 c5c22000 c5c019e0 3fc0: c00493f8 00000000 c5c23ff4 c5c23fd8 c004c2bc c0049404 00000000 00000000 3fe0: 00000000 00000000 00000000 c5c23ff8 c003bc94 c004c26c 00000000 00000000

Backtrace:
[<c007c3fc>] (free_block+0x0/0x158) from [<c007c5fc>] (drain_array+0xa8/0xd8)
[<c007c554>] (drain_array+0x0/0xd8) from [<c007d638>] (cache_reap+0x58/0x120)
 r7:c0304cc0 r6:00000000 r5:c5c00300 r4:c5c02220
[<c007d5e0>] (cache_reap+0x0/0x120) from [<c0048a24>] (run_workqueue+0xbc/0x144)

Quoted 8 lines

[<c0048968>] (run_workqueue+0x0/0x144) from [<c00494e8>] (worker_thread+0xf0/0x104)
r7:c5c23fa4 r6:c5c019e0 r5:c5c22000 r4:c5c019e8
[<c00493f8>] (worker_thread+0x0/0x104) from [<c004c2bc>] (kthread+0x5c/0x94)
r7:00000000 r6:c00493f8 r5:c5c019e0 r4:c5c22000
[<c004c260>] (kthread+0x0/0x94) from [<c003bc94>] (do_exit+0x0/0x5f4)
r6:00000000 r5:00000000 r4:00000000

Code: e592c01c e597e04c e59c2004 e59c3000 (e5823000)
Kernel panic - not syncing: Fatal exception

With CONFIG_MTD_UBI_DEBUG_DISABLE_BGT=y, I get various corruption-caused OOPSes after a remount:

   # umount /cache
   # mount -t ubifs  -o ro ubi:cache /cache

I'm using a 2.6.25 kernel with the 100+ UBIFS-related patches from kernel.org back-ported into it, so some mismatch there is possible.

Hmm, I ran integrity test on UBIFS and had this UBI config option enabled (as well ass emulate write and erase errors options enabled) yesterday, and it worked fine - not slab problems and UBI was able to recover from all errors, so the integrity check test worked fine.

But that was the latest UBIFS from the ubifs-2.6.git tree.

We have UBI/UBIFS backport trees, could you try ubifs-v2.6.26.git please? It has all the UBI/UBIFS patches back-ported. Or you may just take the patches from ubifs-v2.6.26.git and apply them to your tree.

Quoted 6 lines · Artem Bityutskiy

Hmm, I ran integrity test on UBIFS and had this UBI config option enabled (as well ass emulate write and erase errors options enabled) yesterday, and it worked fine - not slab problems and UBI was able to recover from all errors, so the integrity check test worked fine.

But that was the latest UBIFS from the ubifs-2.6.git tree.

Thanks for testing, that helps me narrow the search.

Quoted 3 lines

We have UBI/UBIFS backport trees, could you try ubifs-v2.6.26.git please? It has all the UBI/UBIFS patches back-ported. Or you may just take the patches from ubifs-v2.6.26.git and apply them to your tree.

I assume you meant "ubifs-v2.6.25.git" -- I'm stuck at 2.6.25 for the present due to some out-of-tree drivers. I'll try extracting patches from git://git.infradead.org/~dedekind/ubifs-v2.6.25.git
and applying them to my tree.