From: Bart Van Assche Date: Tue, 10 Mar 2020 04:26:19 +0000 (-0700) Subject: null_blk: Suppress an UBSAN complaint triggered when setting 'memory_backed' X-Git-Tag: v5.10.7~3002^2~43 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=b9853b4d6fb403ccb1d4d82e2d39fc17fc07519c;p=platform%2Fkernel%2Flinux-rpi.git 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 Reviewed-by: Chaitanya Kulkarni Cc: Johannes Thumshirn Cc: Hannes Reinecke Cc: Ming Lei Cc: Christoph Hellwig Signed-off-by: Jens Axboe --- diff --git a/drivers/block/null_blk_main.c b/drivers/block/null_blk_main.c index 1330604..b8a08b8 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);\