Re: [PATCH net-next] mptcp: pm: Fix undefined behavior in mptcp_remove_anno_list_by_saddr()

[Thorsten Blum]

On 25. Mar 2025, at 13:30, Jakub Kicinski wrote:
> On Tue, 25 Mar 2025 12:33:11 +0100 Thorsten Blum wrote:
>> On 25. Mar 2025, at 12:06, Thorsten Blum wrote:
>>> 
>>> Commit e4c28e3d5c090 ("mptcp: pm: move generic PM helpers to pm.c")
>>> removed a necessary if-check, leading to undefined behavior because
>>> the freed pointer is subsequently returned from the function.
>>> 
>>> Reintroduce the if-check to fix this and add a local return variable to
>>> prevent further checkpatch warnings, which originally led to the removal
>>> of the if-check.
>>> 
>>> Fixes: e4c28e3d5c090 ("mptcp: pm: move generic PM helpers to pm.c")
>>> Signed-off-by: Thorsten Blum <thorsten.blum@xxxxxxxxx>
>>> ---  
>> 
>> Never mind, technically it's not actually undefined behavior because of
>> the implicit bool conversion, but returning a freed pointer still seems
>> confusing.
> 
> CCing the list back in.

Thanks!

The change imo still makes sense, but the commit message should be
updated. I'll submit a new patch for after the merge window.