On Tue, Aug 30, 2022 at 12:20 AM Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx> wrote: > > On Mon, 29 Aug 2022, Li Zhong wrote: > > > On Mon, Aug 29, 2022 at 12:09 AM Ilpo Järvinen > > <ilpo.jarvinen@xxxxxxxxxxxxxxx> wrote: > > > > > > On Sun, 28 Aug 2022, Li Zhong wrote: > > > > > > > On Fri, Aug 26, 2022 at 9:01 AM Andy Shevchenko > > > > <andy.shevchenko@xxxxxxxxx> wrote: > > > > > > > > > > On Fri, Aug 26, 2022 at 11:38 AM Li Zhong <floridsleeves@xxxxxxxxx> wrote: > > > > > > > > > > > > uart_port_check() will return NULL pointer when state->uart_port is > > > > > > NULL. Check the return value before dereference it to avoid > > > > > > null-pointer-dereference error. > > > > > > > > > > Have you taken the locking into consideration? > > > > > If no, please do, if yes, expand your commit message to explain why > > > > > the current locking scheme doesn't prevent an error from happening. > > > > > > > > > > > > > The locking is taken into consideration but these three checks do not need to > > > > unlock in error-handling because unlock() will be called in the callers. Will > > > > add the comment in v2 patch. > > > > > > I think he meant you should indicate why the current locking doesn't cover > > > the case you're fixing, not whether this function should call unlock() or > > > not. > > > > > > > Thanks for clarifications. The locking does not guarantee the return value of > > uart_port_check() is not NULL. > > Please put such explanation into the commit message like Andy was asking, > thank you. > Thanks! I'll add this into the v3 patch. > And make sure you properly mention what has changed for any new version > of any patch you send so that Greg don't need to auto-mail you about it > (and end up ignoring your patch). > I'll mention this in the commit message of new patch. > > Actually in line 773 of this file > > (drivers/tty/serial/serial_core.c), uart_port_check() is also called in > > critical section but still there is check on whether the return value is NULL. > > Existance of such a check elsewhere alone isn't enough to guarantee that > the check is necessary (and not even that the check in that other place > would be necessary). You need a deeper analysis than that. I'm not > claiming its either way here, just pointing out to the direction/details > you should consider while writing the analysis of the problem. > Thanks for the suggestions. We will try consider more factor into our analysis tools to reduce false postives. > > -- > i.
