There has been at least one occurrence where a null pointer derefernce
panic was seen with following stack trace.
#0 [ffffff800bcd3800] machine_kexec at ffffff8008095fb4
#1 [ffffff800bcd3860] __crash_kexec at ffffff8008122a30
#2 [ffffff800bcd39f0] panic at ffffff80080aa054
#3 [ffffff800bcd3ae0] die at ffffff800808aee8
#4 [ffffff800bcd3b20] die_kernel_fault at ffffff8008099520
#5 [ffffff800bcd3b50] __do_kernel_fault at ffffff8008098e50
#6 [ffffff800bcd3b80] do_translation_fault at ffffff800809929c
#7 [ffffff800bcd3b90] do_mem_abort at ffffff8008081204
#8 [ffffff800bcd3d90] el1_ia at ffffff800808304c
PC: ffffff80080c20ec [pid_nr_ns+4]
LR: ffffff80080c231c [__task_pid_nr_ns+72]
SP: ffffff800bcd3da0 PSTATE: 60000005
X29: ffffff800bcd3da0 X28: ffffffc00691c380 X27: 0000000000000001
X26: 00000000004ce8e8 X25: 00000000004ce8d0 X24: ffffffc00691c3e0
X23: ffffffc004e8c000 X22: 0000000000000000 X21: ffffffc00b042ed2
X20: ffffff800876a4f0 X19: 0000000000000000 X18: 0000000000000000
X17: 0000000000000001 X16: 0000000000000000 X15: 0000000000000000
X14: 0000000400000003 X13: 0000000000000008 X12: fefefefefefefeff
X11: 0000000000000000 X10: 0000007fffffffff X9: 00000000004ce8b0
X8: 00000000004ce8b0 X7: 0000000000000000 X6: ffffffc00b042ed2
X5: ffffffc00b042ed2 X4: 0000000000020008 X3: 53206e69616c702f
X2: ffffff800876a4f0 X1: ffffff800876a4f0 X0: 53206e69616c702f
#9 [ffffff800bcd3da0] pid_nr_ns at ffffff80080c20e8
Signed-off-by: Alakesh Haloi <[email protected]>
Cc: [email protected]
---
kernel/pid.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/pid.c b/kernel/pid.c
index a96bc4bf4f86..3767b9e1431d 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -474,7 +474,7 @@ pid_t pid_nr_ns(struct pid *pid, struct pid_namespace *ns)
struct upid *upid;
pid_t nr = 0;
- if (pid && ns->level <= pid->level) {
+ if (pid && ns && ns->level <= pid->level) {
upid = &pid->numbers[ns->level];
if (upid->ns == ns)
nr = upid->nr;
--
2.17.1
