The patch titled
Fix NULL ->nsproxy dereference in /proc/*/mounts
has been added to the -mm tree. Its filename is
fix-null-nsproxy-dereference-in-proc-mounts.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: Fix NULL ->nsproxy dereference in /proc/*/mounts
From: Alexey Dobriyan <adobriyan@xxxxxxxxxx>
/proc/*/mounstats was fixed, all right, but...
To reproduce:
while true; do
find /proc -type f 2>/dev/null | xargs cat 1>/dev/null 2>/dev/null;
done
BUG: unable to handle kernel NULL pointer dereference at virtual address 0000000c
printing eip:
c01754df
*pde = 00000000
Oops: 0000 [#28]
Modules linked in: af_packet ohci_hcd e1000 ehci_hcd uhci_hcd usbcore xfs
CPU: 0
EIP: 0060:[<c01754df>] Not tainted VLI
EFLAGS: 00010286 (2.6.20-rc5 #1)
EIP is at mounts_open+0x1c/0xac
eax: 00000000 ebx: d5898ac0 ecx: d1d27b18 edx: d1d27a50
esi: e6083e10 edi: d3c87f38 ebp: d5898ac0 esp: d3c87ef0
ds: 007b es: 007b ss: 0068
Process cat (pid: 18071, ti=d3c86000 task=f7d5f070 task.ti=d3c86000)
Stack: d5898ac0 e6083e10 d3c87f38 c01754c3 c0147c91 c18c52c0 d343f314 d5898ac0
00008000 d3c87f38 ffffff9c c0147e09 d5898ac0 00000000 00000000 c0147e4b
00000000 d3c87f38 d343f314 c18c52c0 c015e53e 00001000 08051000 00000101
Call Trace:
[<c01754c3>] mounts_open+0x0/0xac
[<c0147c91>] __dentry_open+0xa1/0x18c
[<c0147e09>] nameidata_to_filp+0x31/0x3a
[<c0147e4b>] do_filp_open+0x39/0x40
[<c015e53e>] seq_read+0x128/0x2aa
[<c0147e8c>] do_sys_open+0x3a/0x6d
[<c0147efa>] sys_open+0x1c/0x20
[<c0102b76>] sysenter_past_esp+0x5f/0x85
[<c02a0033>] unix_stream_recvmsg+0x3bf/0x4bf
=======================
Code: 5d c3 89 d8 e8 06 e0 f9 ff eb bd 0f 0b eb fe 55 57 56 53 89 d5 8b 40 f0 31 d2 e8 02 c1 fa ff 89 c2 85 c0 74 5c 8b 80 48 04 00 00 <8b> 58 0c 85 db 74 02 ff 03 ff 4a 08 0f 94 c0 84 c0 75 74 85 db
EIP: [<c01754df>] mounts_open+0x1c/0xac SS:ESP 0068:d3c87ef0
A race with do_exit()'s call to exit_namespaces().
Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxxx>
Acked-by: Serge Hallyn <serue@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
fs/proc/base.c | 8 +++++---
1 files changed, 5 insertions(+), 3 deletions(-)
diff -puN fs/proc/base.c~fix-null-nsproxy-dereference-in-proc-mounts fs/proc/base.c
--- a/fs/proc/base.c~fix-null-nsproxy-dereference-in-proc-mounts
+++ a/fs/proc/base.c
@@ -371,9 +371,11 @@ static int mounts_open(struct inode *ino
if (task) {
task_lock(task);
- ns = task->nsproxy->mnt_ns;
- if (ns)
- get_mnt_ns(ns);
+ if (task->nsproxy) {
+ ns = task->nsproxy->mnt_ns;
+ if (ns)
+ get_mnt_ns(ns);
+ }
task_unlock(task);
put_task_struct(task);
}
_
Patches currently in -mm which might be from adobriyan@xxxxxxxxxx are
fix-null-nsproxy-dereference-in-proc-mounts.patch
sysctl_ms_jiffies-fix-oldlen-semantics.patch
consolidate-default-sched_clock.patch
fix-rmmod-read-write-races-in-proc-entries.patch
-
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