Re: Bug - bcache: "unable to handle kernel NULL pointer dereference" when trying to add a md caching device
From: Sebastian Roesner <hidden>
Date: 2016-03-25 14:11:49
Hi Eric, Am 25.03.2016 um 05:18 schrieb Eric Wheeler:
Please send this output: tail /sys/block/md2/queue/discard_*
quoted
git pull https://bitbucket.org/ewheelerinc/linux v4.5-rc6-bcache-fixes git pull https://bitbucket.org/ewheelerinc/linux v4.5-rc7-bcache-fixesTry this patch and see if it BUGs:
> [..] # tail /sys/block/md2/queue/discard_* ==> /sys/block/md2/queue/discard_granularity <== 4096 ==> /sys/block/md2/queue/discard_max_bytes <== 2147450880 ==> /sys/block/md2/queue/discard_max_hw_bytes <== 2147450880 ==> /sys/block/md2/queue/discard_zeroes_data <== 0 root@gropius:/home/sroesner# echo /dev/md2 > /sys/fs/bcache/register sroesner@gropius:~$ -> it killed my bash. Trace with patches and BUG_ON patch: [ 172.660142] BUG: unable to handle kernel NULL pointer dereference at 0000000000000028 [ 172.660229] IP: [<ffffffff811e53b4>] bio_trim+0xf/0x2a [ 172.660289] PGD 7faf3e067 PUD 7f9279067 PMD 0 [ 172.660399] Oops: 0000 [#1] SMP [...] [ 172.664780] Call Trace: [ 172.664813] [<ffffffffa007f3be>] ? raid1_make_request+0x2e8/0xad7 [raid1] [ 172.664846] [<ffffffff811f07da>] ? blk_queue_split+0x377/0x3d4 [ 172.664880] [<ffffffffa005fb5f>] ? md_make_request+0xf6/0x1e9 [md_mod] [ 172.664912] [<ffffffff811eb860>] ? generic_make_request+0xb5/0x155 [ 172.664947] [<ffffffffa0445c89>] ? prio_io+0x85/0x95 [bcache] [ 172.664981] [<ffffffffa0448252>] ? register_cache_set+0x355/0x8d0 [bcache] [ 172.665016] [<ffffffffa04497d3>] ? register_bcache+0x1006/0x1174 [bcache] See http://pastebin.com/6CHtky2x for complete traces. Sebastian