If the core_pattern is set to "|" and any process segfaults then we get a null pointer derefernce while trying to coredump. The call stack shows: [ 108.212680] RIP: 0010:do_coredump+0x628/0x11c0

When the core_pattern has only "|" there is no use of trying the coredump and we can check that while formating the corename and exit with an error.

After this change I get: [ 48.453756] format_corename failed [ 48.453758] Aborting core

Fixes: 315c69261dd3 ("coredump: split pipe command whitespace before expanding template") Reported-by: Matthew Ruffell matthew.ruffell@canonical.com Cc: Paul Wise pabs3@bonedaddy.net Cc: stable@vger.kernel.org Signed-off-by: Sudip Mukherjee sudipm.mukherjee@gmail.com --- fs/coredump.c | 2 ++ 1 file changed, 2 insertions(+)

diff --git a/fs/coredump.c b/fs/coredump.c index f8296a82d01d..408418e6aa13 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -211,6 +211,8 @@ static int format_corename(struct core_name *cn, struct coredump_params *cprm, return -ENOMEM; (*argv)[(*argc)++] = 0; ++pat_ptr; + if (!(*pat_ptr)) + return -ENOMEM; }

/* Repeat as long as we have more pattern to process and more output