[PATCH] posix-timers: fix oops in clock_nanosleep() with CLOCK_MONOTONIC_RAW
Hiroshi Shimamoto
Prevent calling do_nanosleep() with clockid CLOCK_MONOTONIC_RAW, it may
cause oops, such as NULL pointer dereference.
Signed-off-by: Hiroshi Shimamoto <h-shi...@ct.jp.nec.com>
---
kernel/posix-timers.c | 7 +++++++
1 files changed, 7 insertions(+), 0 deletions(-)
diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c
index 052ec4d..d089d05 100644
--- a/kernel/posix-timers.c
+++ b/kernel/posix-timers.c
@@ -202,6 +202,12 @@ static int no_timer_create(struct k_itimer *new_timer)
return -EOPNOTSUPP;
}
+static int no_nsleep(const clockid_t which_clock, int flags,
+ struct timespec *tsave, struct timespec __user *rmtp)
+{
+ return -EOPNOTSUPP;
+}
+
/*
* Return nonzero if we know a priori this clockid_t value is bogus.
*/
@@ -254,6 +260,7 @@ static __init int init_posix_timers(void)
.clock_get = posix_get_monotonic_raw,
.clock_set = do_posix_clock_nosettime,
.timer_create = no_timer_create,
+ .nsleep = no_nsleep,
};
register_posix_clock(CLOCK_REALTIME, &clock_realtime);
--
1.6.3.3
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Andrew Morton
Under which circumstances will this oops trigger?
What userspace setup/actions will trigger the oops?
Thanks.
<spends 5 minutes trying to work out where k_clock.nsleep() even gets
called from>
OK, that CLOCK_DISPATCH() thing should be strangled and burnt...
Hiroshi Shimamoto
Sorry for the lack of information.
Userspace program is like this;
#include <time.h>
int main(void)
{
struct timespec ts;
ts.tv_sec = 1;
ts.tv_nsec = 0;
return clock_nanosleep(4, 0, &ts, NULL);
}
and it will cause oops;
BUG: unable to handle kernel NULL pointer dereference at 0000000000000001
IP: [<ffffffff81029eb5>] __ticket_spin_lock+0x9/0x1a
PGD 3dc6c067 PUD 3b519067 PMD 0
Oops: 0002 [#1] SMP
last sysfs file: /sys/devices/pci0000:00/0000:00:1c.0/0000:02:00.0/irq
CPU 0
Modules linked in: sco bnep l2cap bluetooth sunrpc bridge stp llc ipv6 p4_clockmod speedstep_lib freq_table dm_multipath uinput iTCO_wdt iTCO_vendor_support tg3 i2c_i801 snd_intel8x0 snd_ac97_codec ac97_bus ppdev snd_pcm parport_pc snd_timer floppy parport snd soundcore snd_page_alloc pcspkr ata_generic pata_acpi nouveau drm i2c_algo_bit i2c_core [last unloaded: freq_table]
Pid: 20114, comm: a.out Not tainted 2.6.29.6-213.fc11.x86_64 #1 PC-MY32EXZE78SG
RIP: 0010:[<ffffffff81029eb5>] [<ffffffff81029eb5>] __ticket_spin_lock+0x9/0x1a
RSP: 0018:ffff88003e08bd88 EFLAGS: 00010046
RAX: 0000000000000100 RBX: 0000000000000001 RCX: 0000000000000001
RDX: 000000000000c350 RSI: 0000000000000286 RDI: 0000000000000001
RBP: ffff88003e08bd88 R08: 0000000000000001 R09: 0000003ec680eec0
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000286
R13: ffff88003e08be20 R14: 000000000000c350 R15: 000000000000c350
FS: 00007fb6cd3996f0(0000) GS:ffffffff817b7000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000001 CR3: 000000003a5c0000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process a.out (pid: 20114, threadinfo ffff88003e08a000, task ffff8800399e1700)
Stack:
ffff88003e08bd98 ffffffff81029f7f ffff88003e08bdb8 ffffffff813ac07c
ffff880001011178 ffff88003e08be98 ffff88003e08bde8 ffffffff8105f3a1
ffff88003e08bdd8 ffff88003e08be98 0000000000000001 000000003b9aca00
Call Trace:
[<ffffffff81029f7f>] default_spin_lock_flags+0x9/0xe
[<ffffffff813ac07c>] _spin_lock_irqsave+0x32/0x3b
[<ffffffff8105f3a1>] lock_hrtimer_base+0x2a/0x50
[<ffffffff8105f527>] __hrtimer_start_range_ns+0x2f/0x238
[<ffffffff8105f75e>] hrtimer_start_range_ns+0x14/0x16
[<ffffffff813aac8b>] do_nanosleep+0x4e/0xae
[<ffffffff8105f813>] hrtimer_nanosleep+0xb3/0x123
[<ffffffff8105edea>] ? hrtimer_wakeup+0x0/0x26
[<ffffffff8105b4ed>] sys_clock_nanosleep+0xc9/0xdf
[<ffffffff8101133a>] system_call_fastpath+0x16/0x1b
Code: 9c 02 81 44 89 c6 48 89 c7 e8 0a fb ff ff eb 0f 0f b7 f6 40 0f b6 ff 48 89 c2 e8 1c fb ff ff c9 c3 90 55 b8 00 01 00 00 48 89 e5 <f0> 66 0f c1 07 38 e0 74 06 f3 90 8a 07 eb f6 c9 c3 55 48 89 e5
RIP [<ffffffff81029eb5>] __ticket_spin_lock+0x9/0x1a
RSP <ffff88003e08bd88>
CR2: 0000000000000001
---[ end trace e83b583836779b24 ]---
thanks,
Hiroshi
Andrew Morton
> Userspace program is like this;
>
> #include <time.h>
>
> int main(void)
> {
> struct timespec ts;
>
> ts.tv_sec = 1;
> ts.tv_nsec = 0;
>
> return clock_nanosleep(4, 0, &ts, NULL);
> }
>
> and it will cause oops;
>
> BUG: unable to handle kernel NULL pointer dereference at 0000000000000001
Well that's not very good.
How far back does this go? posix-timers.c hasn't changed in several
kernel versions.
Hiroshi Shimamoto
> On Tue, 04 Aug 2009 16:41:33 +0900 Hiroshi Shimamoto <h-shi...@ct.jp.nec.com> wrote:
>
>> Userspace program is like this;
>>
>> #include <time.h>
>>
>> int main(void)
>> {
>> struct timespec ts;
>>
>> ts.tv_sec = 1;
>> ts.tv_nsec = 0;
>>
>> return clock_nanosleep(4, 0, &ts, NULL);
>> }
>>
>> and it will cause oops;
>>
>> BUG: unable to handle kernel NULL pointer dereference at 0000000000000001
>
> Well that's not very good.
>
> How far back does this go? posix-timers.c hasn't changed in several
> kernel versions.
Not sure the exact version is. I've just noticed it on the latest git and
Fedora 11.
I guess after the below commit;
commit 2d42244ae71d6c7b0884b5664cf2eda30fb2ae68
Author: John Stultz <john...@us.ibm.com>
Date: Wed Aug 20 16:37:30 2008 -0700
clocksource: introduce CLOCK_MONOTONIC_RAW
thanks,
Hiroshi
tip-bot for Hiroshi Shimamoto
Gitweb: http://git.kernel.org/tip/70d715fd0597f18528f389b5ac59102263067744
Author: Hiroshi Shimamoto <h-shi...@ct.jp.nec.com>
AuthorDate: Mon, 3 Aug 2009 11:48:19 +0900
Committer: Ingo Molnar <mi...@elte.hu>
CommitDate: Tue, 4 Aug 2009 10:16:41 +0200
posix-timers: Fix oops in clock_nanosleep() with CLOCK_MONOTONIC_RAW
Prevent calling do_nanosleep() with clockid
CLOCK_MONOTONIC_RAW, it may cause oops, such as NULL pointer
dereference.
Signed-off-by: Hiroshi Shimamoto <h-shi...@ct.jp.nec.com>
Cc: Andrew Morton <ak...@linux-foundation.org>
Cc: Thomas Gleixner <tg...@linutronix.de>
Cc: John Stultz <john...@us.ibm.com>
Cc: <sta...@kernel.org>
LKML-Reference: <4A764FF...@ct.jp.nec.com>
Signed-off-by: Ingo Molnar <mi...@elte.hu>