From: Namhyung Kim Date: Thu, 11 Apr 2013 06:55:01 +0000 (+0900) Subject: tracing: Fix possible NULL pointer dereferences X-Git-Tag: v3.9-rc7~8^2~1 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6a76f8c0ab19f215af2a3442870eeb5f0e81998d;p=pandora-kernel.git tracing: Fix possible NULL pointer dereferences Currently set_ftrace_pid and set_graph_function files use seq_lseek for their fops. However seq_open() is called only for FMODE_READ in the fops->open() so that if an user tries to seek one of those file when she open it for writing, it sees NULL seq_file and then panic. It can be easily reproduced with following command: $ cd /sys/kernel/debug/tracing $ echo 1234 | sudo tee -a set_ftrace_pid In this example, GNU coreutils' tee opens the file with fopen(, "a") and then the fopen() internally calls lseek(). Link: http://lkml.kernel.org/r/1365663302-2170-1-git-send-email-namhyung@kernel.org Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Namhyung Kim Cc: stable@vger.kernel.org Signed-off-by: Namhyung Kim Signed-off-by: Steven Rostedt --- Reading git-diff-tree failed