4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: zhongjiang <zhongjiang@xxxxxxxxxx>
commit 4ea77014af0d6205b05503d1c7aac6eace11d473 upstream.
When running kill(72057458746458112, 0) in userspace I hit the following
issue.
UBSAN: Undefined behaviour in kernel/signal.c:1462:11
negation of -2147483648 cannot be represented in type 'int':
CPU: 226 PID: 9849 Comm: test Tainted: G B ---- ------- 3.10.0-327.53.58.70.x86_64_ubsan+ #116
Hardware name: Huawei Technologies Co., Ltd. RH8100 V3/BC61PBIA, BIOS BLHSV028 11/11/2014
Call Trace:
dump_stack+0x19/0x1b
ubsan_epilogue+0xd/0x50
__ubsan_handle_negate_overflow+0x109/0x14e
SYSC_kill+0x43e/0x4d0
SyS_kill+0xe/0x10
system_call_fastpath+0x16/0x1b
Add code to avoid the UBSAN detection.
[akpm@xxxxxxxxxxxxxxxxxxxx: tweak comment]
Link: http://lkml.kernel.org/r/1496670008-59084-1-git-send-email-zhongjiang@xxxxxxxxxx
Signed-off-by: zhongjiang <zhongjiang@xxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Xishi Qiu <qiuxishi@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/signal.c | 4 ++++
1 file changed, 4 insertions(+)
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1392,6 +1392,10 @@ static int kill_something_info(int sig,
return ret;
}
+ /* -INT_MIN is undefined. Exclude this case to avoid a UBSAN warning */
+ if (pid == INT_MIN)
+ return -ESRCH;
+
read_lock(&tasklist_lock);
if (pid != -1) {
ret = __kill_pgrp_info(sig, info,
