We encountered following panic. Validate the pointer to avoid this. [35046.276380] BUG: unable to handle kernel NULL pointer dereference at 00000010 [35046.283316] IP: [<8095dc91>] copy_mnt_ns+0x111/0x260 [35046.288225] *pdpt = 000000001b883001 *pde = 0000000000000000 [35046.293901] Oops: 0000 [#1] PREEMPT SMP [35046.307342] CPU: 2 PID: 6761 Comm: main Tainted: G W O [35046.315345] task: a7f06f80 ti: 82e16000 task.ti: 82e16000 [35046.320673] EIP: 0060:[<8095dc91>] EFLAGS: 00210246 CPU: 2 [35046.326106] EIP is at copy_mnt_ns+0x111/0x260 [35046.330397] EAX: 3436362e EBX: b1026880 ECX: 96822f80 EDX: 828314a8 [35046.336590] ESI: 00000000 EDI: b0dde300 EBP: 82e17f50 ESP: 82e17f24 [35046.342789] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 [35046.348124] CR0: 8005003b CR2: 00000010 CR3: 033c6000 CR4: 00102720 [35046.354397] DR0: 00000000 DR1: 00000001 DR2: 00000002 DR3: 00000003 [35046.360525] DR6: 00000006 DR7: 00000007 [35046.364299] Stack: [35046.366278] 828314a8 96822f80 82831490 82831490 82831490 a3161780 82831480 00000018 [35046.373932] a7f06f80 a4c130d8 00020200 82e17f6c 8085f98d b1026880 8134b920 00020200 [35046.381593] 8134b920 82e17f9c 82e17f84 8085fbcf b1026880 00020200 ffffffea 00000000 [35046.389259] Call Trace: [35046.391693] [<8085f98d>] create_new_namespaces+0x4d/0x160 [35046.397106] [<8085fbcf>] unshare_nsproxy_namespaces+0x5f/0xa0 [35046.402870] [<8083c7c4>] SyS_unshare+0x104/0x240 [35046.407518] [<80fe1700>] syscall_call+0x7/0xb Signed-off-by: Leon Ma <xindong.ma@xxxxxxxxx> --- fs/namespace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/namespace.c b/fs/namespace.c index 1f4f9da..1c61c92 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -2788,7 +2788,7 @@ struct mnt_namespace *copy_mnt_ns(unsigned long flags, struct mnt_namespace *ns, q = next_mnt(q, new); if (!q) break; - while (p->mnt.mnt_root != q->mnt.mnt_root) + while (p && p->mnt.mnt_root != q->mnt.mnt_root) p = next_mnt(p, old); } namespace_unlock(); -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
