From: Bart Van Assche <bvanassche@acm.org>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
Bart Van Assche <bvanassche@acm.org>,
Christoph Hellwig <hch@infradead.org>,
Ming Lei <ming.lei@redhat.com>, Hannes Reinecke <hare@suse.com>,
Johannes Thumshirn <jth@kernel.org>
Subject: [PATCH v2 4/8] null_blk: Suppress an UBSAN complaint triggered when setting 'memory_backed'
Date: Wed, 19 Feb 2020 18:44:37 -0800 [thread overview]
Message-ID: <20200220024441.11558-5-bvanassche@acm.org> (raw)
In-Reply-To: <20200220024441.11558-1-bvanassche@acm.org>
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
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Johannes Thumshirn <jth@kernel.org>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
drivers/block/null_blk_main.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/block/null_blk_main.c b/drivers/block/null_blk_main.c
index 16510795e377..7cd31d4ef709 100644
--- a/drivers/block/null_blk_main.c
+++ b/drivers/block/null_blk_main.c
@@ -276,7 +276,7 @@ nullb_device_##NAME##_store(struct config_item *item, const char *page, \
{ \
int (*apply_fn)(struct nullb_device *dev, TYPE new_value) = APPLY;\
struct nullb_device *dev = to_nullb_device(item); \
- TYPE uninitialized_var(new_value); \
+ TYPE new_value = 0; \
int ret; \
\
ret = nullb_device_##TYPE##_attr_store(&new_value, page, count);\
next prev parent reply other threads:[~2020-02-20 2:44 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-20 2:44 [PATCH v2 0/8] Eight patches related to changing the number of hardware queues Bart Van Assche
2020-02-20 2:44 ` [PATCH v2 1/8] blk-mq: Fix a comment in include/linux/blk-mq.h Bart Van Assche
2020-02-20 2:44 ` [PATCH v2 2/8] blk-mq: Keep set->nr_hw_queues and set->map[].nr_queues in sync Bart Van Assche
2020-02-20 10:05 ` Ming Lei
2020-02-20 16:14 ` Bart Van Assche
2020-02-20 20:47 ` Ming Lei
2020-02-21 2:50 ` Bart Van Assche
2020-02-20 2:44 ` [PATCH v2 3/8] blk-mq: Fix a recently introduced regression in blk_mq_realloc_hw_ctxs() Bart Van Assche
2020-02-20 2:44 ` Bart Van Assche [this message]
2020-02-20 2:44 ` [PATCH v2 5/8] null_blk: Fix changing the number of hardware queues Bart Van Assche
2020-02-20 2:44 ` [PATCH v2 6/8] null_blk: Fix the null_add_dev() error path Bart Van Assche
2020-02-20 2:44 ` [PATCH v2 7/8] null_blk: Handle null_add_dev() failures properly Bart Van Assche
2020-02-20 2:44 ` [PATCH v2 8/8] null_blk: Add support for init_hctx() fault injection Bart Van Assche
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