On Sat, Nov 13, 2021 at 08:20:13PM +0300, Pavel Skripkin wrote:
Access to netdev after free_netdev() will cause use-after-free bug. Move debug log before free_netdev() call to avoid it.
Cc: stable@vger.kernel.org # v4.19+ Signed-off-by: Pavel Skripkin paskripkin@gmail.com
Note about Fixes: tag. The commit introduced it was before this driver was moved out from staging. I guess, Fixes tag cannot be used here. Please, let me know if I am wrong.
You should still use the Fixes tag.
Cc: Dan Carpenter dan.carpenter@oracle.com
@Dan, is there a smatch checker for straigthforward use after free bugs? Like acessing pointer after free was called? I think, adding free_netdev() to check list might be good idea
I've skimmed througth smatch source and didn't find one, so can you, please, point out to it if it exists.
It's check_free_strict.c.
It does cross function analysis but free_netdev() is tricky because it doesn't free directly, it just drops the reference count. Also it delays freeing in the NETREG_UNREGISTERING path so this check might cause false positives? I'll add free_netdev() to the list of free functions and test it overnight tonight.
register_free_hook("free_netdev", &match_free, 0);
regards, dan carpenter