Re: [PATCH] selftests/resctrl: Fix null pointer dereference on open failed

From: Shuah Khan
Date: Mon Apr 25 2022 - 12:21:35 EST

On 4/25/22 10:06 AM, Colin King (gmail) wrote:
On 25/04/2022 16:51, Shuah Khan wrote:
On 4/24/22 3:15 PM, Colin Ian King wrote:
Currently if opening /dev/null fails to open then file pointer fp
is null and further access to fp via fprintf will cause a null
pointer dereference. Fix this by returning a negative error value
when a null fp is detected.

How did you find this problem and how can it be reproduced? Is there
a case where test fails to open "/dev/null"?

Found with static analysis, cppcheck. Open on /dev/null is unlikely to fail, but it's good to fail reliably rather than have a SIGSEGV :-)

I don't see how /dev/null open could fail here in this test.
However, I will take this fix. Please add information how
you found it and include the cppheck log in the commit log
and send me v2.

-- Shuah