null_blk: Suppress an UBSAN complaint triggered when setting 'memory_backed'
authorBart Van Assche <bvanassche@acm.org>
Tue, 10 Mar 2020 04:26:19 +0000 (21:26 -0700)
committerJens Axboe <axboe@kernel.dk>
Tue, 10 Mar 2020 13:09:59 +0000 (07:09 -0600)
commitb9853b4d6fb403ccb1d4d82e2d39fc17fc07519c
tree43bb5f7b44fb8a281d9a9d751e9888c78b47e793
parentd0930bb8f46b8fb4a7d429c0bf1c91b3ed00a7cf
null_blk: Suppress an UBSAN complaint triggered when setting 'memory_backed'

Although it is not clear to me why UBSAN complains when 'memory_backed'
is set, this patch suppresses the UBSAN complaint that is triggered when
setting that configfs attribute.

UBSAN: Undefined behaviour in drivers/block/null_blk_main.c:327:1
load of value 16 is not a valid value for type '_Bool'
CPU: 2 PID: 8396 Comm: check Not tainted 5.6.0-rc1-dbg+ #14
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
Call Trace:
 dump_stack+0xa5/0xe6
 ubsan_epilogue+0x9/0x26
 __ubsan_handle_load_invalid_value+0x6d/0x76
 nullb_device_memory_backed_store.cold+0x2c/0x38 [null_blk]
 configfs_write_file+0x1c4/0x250 [configfs]
 __vfs_write+0x4c/0x90
 vfs_write+0x145/0x2c0
 ksys_write+0xd7/0x180
 __x64_sys_write+0x47/0x50
 do_syscall_64+0x6f/0x2f0
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Cc: Johannes Thumshirn <jth@kernel.org>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
drivers/block/null_blk_main.c