On Thu, 2018-07-26 at 22:22 +-0800, Coly Li wrote: +AD4- Global variable bcache+AF8-debug is firstly initialized in bch+AF8-debug+AF8-init(), +AD4- and destroyed in bch+AF8-debug+AF8-exit(). bch+AF8-debug+AF8-init() is called in +AD4- bcache+AF8-init() with many other functions, if one of the previous calling +AD4- onces failed, bcache+AF8-exit() will be called in the failure path. +AD4- +AD4- The problem is, if bcache+AF8-init() fails before bch+AF8-debug+AF8-init() is called, +AD4- then in bcache+AF8-exit() when bch+AF8-debug+AF8-exit() is called to destroy global +AD4- variable bcache+AF8-debug, at this moment bcache+AF8-debug is unndefined, then the +AD4- test of +ACI-if (+ACE-IS+AF8-ERR+AF8-OR+AF8-NULL(bcache+AF8-debug))+ACI- might be buggy. +AD4- +AD4- This patch initializes global varabile bcache+AF8-debug to be NULL, to make +AD4- the failure code path to be predictable. +AD4- +AD4- Signed-off-by: Coly Li +ADw-colyli+AEA-suse.de+AD4- +AD4- --- +AD4- drivers/md/bcache/debug.c +AHw- 2 +-- +AD4- 1 file changed, 1 insertion(+-), 1 deletion(-) +AD4- +AD4- diff --git a/drivers/md/bcache/debug.c b/drivers/md/bcache/debug.c +AD4- index 57f8f5aeee55..24b0eb65ddec 100644 +AD4- --- a/drivers/md/bcache/debug.c +AD4- +-+-+- b/drivers/md/bcache/debug.c +AD4- +AEAAQA- -17,7 +-17,7 +AEAAQA- +AD4- +ACM-include +ADw-linux/random.h+AD4- +AD4- +ACM-include +ADw-linux/seq+AF8-file.h+AD4- +AD4- +AD4- -struct dentry +ACo-bcache+AF8-debug+ADs- +AD4- +-struct dentry +ACo-bcache+AF8-debug +AD0- NULL+ADs- +AD4- +AD4- +ACM-ifdef CONFIG+AF8-BCACHE+AF8-DEBUG Please verify patches with checkpatch before posting these. Checkpatch is namely able to detect that this patch is useless: +ACQ- scripts/checkpatch.pl +AFwAWw-PATCH+AF8-8+AF8-9+AFwAXQBf-bcache+AFw-:+AF8-initiate+AF8-bcache+AF8-debug+AF8-to+AF8-NULL.mbox ERROR: do not initialise globals to NULL +ACM-217: FILE: drivers/md/bcache/debug.c:20: +-struct dentry +ACo-bcache+AF8-debug +AD0- NULL+ADs- Bart. -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
