2008-02-01 13:36:00

by Oleg Nesterov

[permalink] [raw]
Subject: [PATCH 2/5] hrtimer_nanosleep: fix *rmtp handling

Spotted by Pavel Emelyanov and Alexey Dobriyan.

hrtimer_nanosleep() sets restart_block->arg1 = rmtp, but this rmtp points to
the local variable which lives in the caller's stack frame. This means that
if sys_restart_syscall() actually happens and it is interrupted as well, we
don't the user-space variable, but write into the already dead stack frame.

Change the callers to pass "__user *rmtp" to hrtimer_nanosleep(), and change
hrtimer_nanosleep() to use copy_to_user() to actually update *rmtp.

Small problem remains. man 2 nanosleep states that *rtmp should be written if
nanosleep() was interrupted (it says nothing whether it is OK to update *rmtp
if nanosleep returns 0), but (with or without this patch) we can disty *rem
even if nanosleep() returns 0.

NOTE: this patch doesn't change compat_sys_nanosleep(), because it has other
bugs. Fixed by the next patch.

Signed-off-by: Oleg Nesterov <[email protected]>

include/linux/hrtimer.h | 2 -
kernel/hrtimer.c | 51 +++++++++++++++++++++++++-----------------------
kernel/posix-timers.c | 14 +------------
3 files changed, 30 insertions(+), 37 deletions(-)

--- MM/include/linux/hrtimer.h~HRT_RMTP 2008-01-27 17:07:39.000000000 +0300
+++ MM/include/linux/hrtimer.h 2008-01-31 14:01:53.000000000 +0300
@@ -313,7 +313,7 @@ static inline u64 hrtimer_forward_now(st

/* Precise sleep: */
extern long hrtimer_nanosleep(struct timespec *rqtp,
- struct timespec *rmtp,
+ struct timespec __user *rmtp,
const enum hrtimer_mode mode,
const clockid_t clockid);
extern long hrtimer_nanosleep_restart(struct restart_block *restart_block);
--- MM/kernel/hrtimer.c~HRT_RMTP 2008-02-01 13:43:52.000000000 +0300
+++ MM/kernel/hrtimer.c 2008-02-01 13:56:44.000000000 +0300
@@ -1317,11 +1317,26 @@ static int __sched do_nanosleep(struct h
return t->task == NULL;
}

+static int update_rmtp(struct hrtimer *timer, struct timespec __user *rmtp)
+{
+ struct timespec rmt;
+ ktime_t rem;
+
+ rem = ktime_sub(timer->expires, timer->base->get_time());
+ if (rem.tv64 <= 0)
+ return 0;
+ rmt = ktime_to_timespec(rem);
+
+ if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
+ return -EFAULT;
+
+ return 1;
+}
+
long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
{
struct hrtimer_sleeper t;
- struct timespec *rmtp;
- ktime_t time;
+ struct timespec __user *rmtp;

restart->fn = do_no_restart_syscall;

@@ -1331,12 +1346,11 @@ long __sched hrtimer_nanosleep_restart(s
if (do_nanosleep(&t, HRTIMER_MODE_ABS))
return 0;

- rmtp = (struct timespec *)restart->arg1;
+ rmtp = (struct timespec __user *)restart->arg1;
if (rmtp) {
- time = ktime_sub(t.timer.expires, t.timer.base->get_time());
- if (time.tv64 <= 0)
- return 0;
- *rmtp = ktime_to_timespec(time);
+ int ret = update_rmtp(&t.timer, rmtp);
+ if (ret <= 0)
+ return ret;
}

restart->fn = hrtimer_nanosleep_restart;
@@ -1345,12 +1359,11 @@ long __sched hrtimer_nanosleep_restart(s
return -ERESTART_RESTARTBLOCK;
}

-long hrtimer_nanosleep(struct timespec *rqtp, struct timespec *rmtp,
+long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
const enum hrtimer_mode mode, const clockid_t clockid)
{
struct restart_block *restart;
struct hrtimer_sleeper t;
- ktime_t rem;

hrtimer_init(&t.timer, clockid, mode);
t.timer.expires = timespec_to_ktime(*rqtp);
@@ -1362,10 +1375,9 @@ long hrtimer_nanosleep(struct timespec *
return -EINTR;

if (rmtp) {
- rem = ktime_sub(t.timer.expires, t.timer.base->get_time());
- if (rem.tv64 <= 0)
- return 0;
- *rmtp = ktime_to_timespec(rem);
+ int ret = update_rmtp(&t.timer, rmtp);
+ if (ret <= 0)
+ return ret;
}

restart = &current_thread_info()->restart_block;
@@ -1381,8 +1393,7 @@ long hrtimer_nanosleep(struct timespec *
asmlinkage long
sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp)
{
- struct timespec tu, rmt;
- int ret;
+ struct timespec tu;

if (copy_from_user(&tu, rqtp, sizeof(tu)))
return -EFAULT;
@@ -1390,15 +1401,7 @@ sys_nanosleep(struct timespec __user *rq
if (!timespec_valid(&tu))
return -EINVAL;

- ret = hrtimer_nanosleep(&tu, rmtp ? &rmt : NULL, HRTIMER_MODE_REL,
- CLOCK_MONOTONIC);
-
- if (ret && rmtp) {
- if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
- return -EFAULT;
- }
-
- return ret;
+ return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
}

/*
--- MM/kernel/posix-timers.c~HRT_RMTP 2008-01-27 17:07:40.000000000 +0300
+++ MM/kernel/posix-timers.c 2008-02-01 13:18:51.000000000 +0300
@@ -982,20 +982,10 @@ sys_clock_getres(const clockid_t which_c
static int common_nsleep(const clockid_t which_clock, int flags,
struct timespec *tsave, struct timespec __user *rmtp)
{
- struct timespec rmt;
- int ret;
-
- ret = hrtimer_nanosleep(tsave, rmtp ? &rmt : NULL,
+ return hrtimer_nanosleep(tsave, rmtp,
flags & TIMER_ABSTIME ?
- HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
+ HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
which_clock);
-
- if (ret && rmtp) {
- if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
- return -EFAULT;
- }
-
- return ret;
}

asmlinkage long


2008-02-01 13:50:37

by Thomas Gleixner

[permalink] [raw]
Subject: Re: [PATCH 2/5] hrtimer_nanosleep: fix *rmtp handling

On Fri, 1 Feb 2008, Oleg Nesterov wrote:

> Spotted by Pavel Emelyanov and Alexey Dobriyan.

Doh, yes. This was introduced by:

04c227140fed77587432667a574b14736a06dd7f

I did not notice, when I picked up the patch.

Thanks for fixing this,

tglx

> hrtimer_nanosleep() sets restart_block->arg1 = rmtp, but this rmtp points to
> the local variable which lives in the caller's stack frame. This means that
> if sys_restart_syscall() actually happens and it is interrupted as well, we
> don't the user-space variable, but write into the already dead stack frame.
>
> Change the callers to pass "__user *rmtp" to hrtimer_nanosleep(), and change
> hrtimer_nanosleep() to use copy_to_user() to actually update *rmtp.
>
> Small problem remains. man 2 nanosleep states that *rtmp should be written if
> nanosleep() was interrupted (it says nothing whether it is OK to update *rmtp
> if nanosleep returns 0), but (with or without this patch) we can disty *rem
> even if nanosleep() returns 0.
>
> NOTE: this patch doesn't change compat_sys_nanosleep(), because it has other
> bugs. Fixed by the next patch.
>
> Signed-off-by: Oleg Nesterov <[email protected]>
>
> include/linux/hrtimer.h | 2 -
> kernel/hrtimer.c | 51 +++++++++++++++++++++++++-----------------------
> kernel/posix-timers.c | 14 +------------
> 3 files changed, 30 insertions(+), 37 deletions(-)
>
> --- MM/include/linux/hrtimer.h~HRT_RMTP 2008-01-27 17:07:39.000000000 +0300
> +++ MM/include/linux/hrtimer.h 2008-01-31 14:01:53.000000000 +0300
> @@ -313,7 +313,7 @@ static inline u64 hrtimer_forward_now(st
>
> /* Precise sleep: */
> extern long hrtimer_nanosleep(struct timespec *rqtp,
> - struct timespec *rmtp,
> + struct timespec __user *rmtp,
> const enum hrtimer_mode mode,
> const clockid_t clockid);
> extern long hrtimer_nanosleep_restart(struct restart_block *restart_block);
> --- MM/kernel/hrtimer.c~HRT_RMTP 2008-02-01 13:43:52.000000000 +0300
> +++ MM/kernel/hrtimer.c 2008-02-01 13:56:44.000000000 +0300
> @@ -1317,11 +1317,26 @@ static int __sched do_nanosleep(struct h
> return t->task == NULL;
> }
>
> +static int update_rmtp(struct hrtimer *timer, struct timespec __user *rmtp)
> +{
> + struct timespec rmt;
> + ktime_t rem;
> +
> + rem = ktime_sub(timer->expires, timer->base->get_time());
> + if (rem.tv64 <= 0)
> + return 0;
> + rmt = ktime_to_timespec(rem);
> +
> + if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
> + return -EFAULT;
> +
> + return 1;
> +}
> +
> long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
> {
> struct hrtimer_sleeper t;
> - struct timespec *rmtp;
> - ktime_t time;
> + struct timespec __user *rmtp;
>
> restart->fn = do_no_restart_syscall;
>
> @@ -1331,12 +1346,11 @@ long __sched hrtimer_nanosleep_restart(s
> if (do_nanosleep(&t, HRTIMER_MODE_ABS))
> return 0;
>
> - rmtp = (struct timespec *)restart->arg1;
> + rmtp = (struct timespec __user *)restart->arg1;
> if (rmtp) {
> - time = ktime_sub(t.timer.expires, t.timer.base->get_time());
> - if (time.tv64 <= 0)
> - return 0;
> - *rmtp = ktime_to_timespec(time);
> + int ret = update_rmtp(&t.timer, rmtp);
> + if (ret <= 0)
> + return ret;
> }
>
> restart->fn = hrtimer_nanosleep_restart;
> @@ -1345,12 +1359,11 @@ long __sched hrtimer_nanosleep_restart(s
> return -ERESTART_RESTARTBLOCK;
> }
>
> -long hrtimer_nanosleep(struct timespec *rqtp, struct timespec *rmtp,
> +long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
> const enum hrtimer_mode mode, const clockid_t clockid)
> {
> struct restart_block *restart;
> struct hrtimer_sleeper t;
> - ktime_t rem;
>
> hrtimer_init(&t.timer, clockid, mode);
> t.timer.expires = timespec_to_ktime(*rqtp);
> @@ -1362,10 +1375,9 @@ long hrtimer_nanosleep(struct timespec *
> return -EINTR;
>
> if (rmtp) {
> - rem = ktime_sub(t.timer.expires, t.timer.base->get_time());
> - if (rem.tv64 <= 0)
> - return 0;
> - *rmtp = ktime_to_timespec(rem);
> + int ret = update_rmtp(&t.timer, rmtp);
> + if (ret <= 0)
> + return ret;
> }
>
> restart = &current_thread_info()->restart_block;
> @@ -1381,8 +1393,7 @@ long hrtimer_nanosleep(struct timespec *
> asmlinkage long
> sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp)
> {
> - struct timespec tu, rmt;
> - int ret;
> + struct timespec tu;
>
> if (copy_from_user(&tu, rqtp, sizeof(tu)))
> return -EFAULT;
> @@ -1390,15 +1401,7 @@ sys_nanosleep(struct timespec __user *rq
> if (!timespec_valid(&tu))
> return -EINVAL;
>
> - ret = hrtimer_nanosleep(&tu, rmtp ? &rmt : NULL, HRTIMER_MODE_REL,
> - CLOCK_MONOTONIC);
> -
> - if (ret && rmtp) {
> - if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
> - return -EFAULT;
> - }
> -
> - return ret;
> + return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
> }
>
> /*
> --- MM/kernel/posix-timers.c~HRT_RMTP 2008-01-27 17:07:40.000000000 +0300
> +++ MM/kernel/posix-timers.c 2008-02-01 13:18:51.000000000 +0300
> @@ -982,20 +982,10 @@ sys_clock_getres(const clockid_t which_c
> static int common_nsleep(const clockid_t which_clock, int flags,
> struct timespec *tsave, struct timespec __user *rmtp)
> {
> - struct timespec rmt;
> - int ret;
> -
> - ret = hrtimer_nanosleep(tsave, rmtp ? &rmt : NULL,
> + return hrtimer_nanosleep(tsave, rmtp,
> flags & TIMER_ABSTIME ?
> - HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
> + HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
> which_clock);
> -
> - if (ret && rmtp) {
> - if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
> - return -EFAULT;
> - }
> -
> - return ret;
> }
>
> asmlinkage long
>

2008-02-01 14:26:50

by Oleg Nesterov

[permalink] [raw]
Subject: Re: [PATCH 2/5] hrtimer_nanosleep: fix *rmtp handling

(Andrew, the same patch, but re-diffed without the first one in series).


[PATCH 2/5] hrtimer_nanosleep: fix *rmtp handling

Spotted by Pavel Emelyanov and Alexey Dobriyan.

hrtimer_nanosleep() sets restart_block->arg1 = rmtp, but this rmtp points to
the local variable which lives in the caller's stack frame. This means that
if sys_restart_syscall() actually happens and it is interrupted as well, we
don't update the user-space variable, but write into the already dead stack
frame.

Change the callers to pass "__user *rmtp" to hrtimer_nanosleep(), and change
hrtimer_nanosleep() to use copy_to_user() to actually update *rmtp.

Small problem remains. man 2 nanosleep states that *rtmp should be written if
nanosleep() was interrupted (it says nothing whether it is OK to update *rmtp
if nanosleep returns 0), but (with or without this patch) we can dirty *rem
even if nanosleep() returns 0.

NOTE: this patch doesn't change compat_sys_nanosleep(), because it has other
bugs. Fixed by the next patch.

Signed-off-by: Oleg Nesterov <[email protected]>

include/linux/hrtimer.h | 2 -
kernel/hrtimer.c | 51 +++++++++++++++++++++++++-----------------------
kernel/posix-timers.c | 14 +------------
3 files changed, 30 insertions(+), 37 deletions(-)

--- MM/include/linux/hrtimer.h~HRT_RMTP 2008-01-27 17:07:39.000000000 +0300
+++ MM/include/linux/hrtimer.h 2008-01-31 14:01:53.000000000 +0300
@@ -313,7 +313,7 @@ static inline u64 hrtimer_forward_now(st

/* Precise sleep: */
extern long hrtimer_nanosleep(struct timespec *rqtp,
- struct timespec *rmtp,
+ struct timespec __user *rmtp,
const enum hrtimer_mode mode,
const clockid_t clockid);
extern long hrtimer_nanosleep_restart(struct restart_block *restart_block);
--- MM/kernel/hrtimer.c~HRT_RMTP 2008-02-01 13:43:52.000000000 +0300
+++ MM/kernel/hrtimer.c 2008-02-01 13:56:44.000000000 +0300
@@ -1317,11 +1317,26 @@ static int __sched do_nanosleep(struct h
return t->task == NULL;
}

+static int update_rmtp(struct hrtimer *timer, struct timespec __user *rmtp)
+{
+ struct timespec rmt;
+ ktime_t rem;
+
+ rem = ktime_sub(timer->expires, timer->base->get_time());
+ if (rem.tv64 <= 0)
+ return 0;
+ rmt = ktime_to_timespec(rem);
+
+ if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
+ return -EFAULT;
+
+ return 1;
+}
+
long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
{
struct hrtimer_sleeper t;
- struct timespec *rmtp;
- ktime_t time;
+ struct timespec __user *rmtp;

restart->fn = do_no_restart_syscall;

@@ -1331,12 +1346,11 @@ long __sched hrtimer_nanosleep_restart(s
if (do_nanosleep(&t, HRTIMER_MODE_ABS))
return 0;

- rmtp = (struct timespec *)restart->arg1;
+ rmtp = (struct timespec __user *)restart->arg1;
if (rmtp) {
- time = ktime_sub(t.timer.expires, t.timer.base->get_time());
- if (time.tv64 <= 0)
- return 0;
- *rmtp = ktime_to_timespec(time);
+ int ret = update_rmtp(&t.timer, rmtp);
+ if (ret <= 0)
+ return ret;
}

restart->fn = hrtimer_nanosleep_restart;
@@ -1345,12 +1359,11 @@ long __sched hrtimer_nanosleep_restart(s
return -ERESTART_RESTARTBLOCK;
}

-long hrtimer_nanosleep(struct timespec *rqtp, struct timespec *rmtp,
+long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
const enum hrtimer_mode mode, const clockid_t clockid)
{
struct restart_block *restart;
struct hrtimer_sleeper t;
- ktime_t rem;

hrtimer_init(&t.timer, clockid, mode);
t.timer.expires = timespec_to_ktime(*rqtp);
@@ -1362,10 +1375,9 @@ long hrtimer_nanosleep(struct timespec *
return -ERESTARTNOHAND;

if (rmtp) {
- rem = ktime_sub(t.timer.expires, t.timer.base->get_time());
- if (rem.tv64 <= 0)
- return 0;
- *rmtp = ktime_to_timespec(rem);
+ int ret = update_rmtp(&t.timer, rmtp);
+ if (ret <= 0)
+ return ret;
}

restart = &current_thread_info()->restart_block;
@@ -1381,8 +1393,7 @@ long hrtimer_nanosleep(struct timespec *
asmlinkage long
sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp)
{
- struct timespec tu, rmt;
- int ret;
+ struct timespec tu;

if (copy_from_user(&tu, rqtp, sizeof(tu)))
return -EFAULT;
@@ -1390,15 +1401,7 @@ sys_nanosleep(struct timespec __user *rq
if (!timespec_valid(&tu))
return -EINVAL;

- ret = hrtimer_nanosleep(&tu, rmtp ? &rmt : NULL, HRTIMER_MODE_REL,
- CLOCK_MONOTONIC);
-
- if (ret && rmtp) {
- if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
- return -EFAULT;
- }
-
- return ret;
+ return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
}

/*
--- MM/kernel/posix-timers.c~HRT_RMTP 2008-01-27 17:07:40.000000000 +0300
+++ MM/kernel/posix-timers.c 2008-02-01 13:18:51.000000000 +0300
@@ -982,20 +982,10 @@ sys_clock_getres(const clockid_t which_c
static int common_nsleep(const clockid_t which_clock, int flags,
struct timespec *tsave, struct timespec __user *rmtp)
{
- struct timespec rmt;
- int ret;
-
- ret = hrtimer_nanosleep(tsave, rmtp ? &rmt : NULL,
+ return hrtimer_nanosleep(tsave, rmtp,
flags & TIMER_ABSTIME ?
- HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
+ HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
which_clock);
-
- if (ret && rmtp) {
- if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
- return -EFAULT;
- }
-
- return ret;
}

asmlinkage long

2008-02-01 15:18:19

by Thomas Gleixner

[permalink] [raw]
Subject: Re: [PATCH 2/5] hrtimer_nanosleep: fix *rmtp handling

On Fri, 1 Feb 2008, Oleg Nesterov wrote:

> (Andrew, the same patch, but re-diffed without the first one in series).

I pick them up and feed them through hrtimer.git, once all bugs are
shaken out :)

Thanks,
tglx

> [PATCH 2/5] hrtimer_nanosleep: fix *rmtp handling
>
> Spotted by Pavel Emelyanov and Alexey Dobriyan.
>
> hrtimer_nanosleep() sets restart_block->arg1 = rmtp, but this rmtp points to
> the local variable which lives in the caller's stack frame. This means that
> if sys_restart_syscall() actually happens and it is interrupted as well, we
> don't update the user-space variable, but write into the already dead stack
> frame.
>
> Change the callers to pass "__user *rmtp" to hrtimer_nanosleep(), and change
> hrtimer_nanosleep() to use copy_to_user() to actually update *rmtp.
>
> Small problem remains. man 2 nanosleep states that *rtmp should be written if
> nanosleep() was interrupted (it says nothing whether it is OK to update *rmtp
> if nanosleep returns 0), but (with or without this patch) we can dirty *rem
> even if nanosleep() returns 0.
>
> NOTE: this patch doesn't change compat_sys_nanosleep(), because it has other
> bugs. Fixed by the next patch.
>
> Signed-off-by: Oleg Nesterov <[email protected]>
>
> include/linux/hrtimer.h | 2 -
> kernel/hrtimer.c | 51 +++++++++++++++++++++++++-----------------------
> kernel/posix-timers.c | 14 +------------
> 3 files changed, 30 insertions(+), 37 deletions(-)
>
> --- MM/include/linux/hrtimer.h~HRT_RMTP 2008-01-27 17:07:39.000000000 +0300
> +++ MM/include/linux/hrtimer.h 2008-01-31 14:01:53.000000000 +0300
> @@ -313,7 +313,7 @@ static inline u64 hrtimer_forward_now(st
>
> /* Precise sleep: */
> extern long hrtimer_nanosleep(struct timespec *rqtp,
> - struct timespec *rmtp,
> + struct timespec __user *rmtp,
> const enum hrtimer_mode mode,
> const clockid_t clockid);
> extern long hrtimer_nanosleep_restart(struct restart_block *restart_block);
> --- MM/kernel/hrtimer.c~HRT_RMTP 2008-02-01 13:43:52.000000000 +0300
> +++ MM/kernel/hrtimer.c 2008-02-01 13:56:44.000000000 +0300
> @@ -1317,11 +1317,26 @@ static int __sched do_nanosleep(struct h
> return t->task == NULL;
> }
>
> +static int update_rmtp(struct hrtimer *timer, struct timespec __user *rmtp)
> +{
> + struct timespec rmt;
> + ktime_t rem;
> +
> + rem = ktime_sub(timer->expires, timer->base->get_time());
> + if (rem.tv64 <= 0)
> + return 0;
> + rmt = ktime_to_timespec(rem);
> +
> + if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
> + return -EFAULT;
> +
> + return 1;
> +}
> +
> long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
> {
> struct hrtimer_sleeper t;
> - struct timespec *rmtp;
> - ktime_t time;
> + struct timespec __user *rmtp;
>
> restart->fn = do_no_restart_syscall;
>
> @@ -1331,12 +1346,11 @@ long __sched hrtimer_nanosleep_restart(s
> if (do_nanosleep(&t, HRTIMER_MODE_ABS))
> return 0;
>
> - rmtp = (struct timespec *)restart->arg1;
> + rmtp = (struct timespec __user *)restart->arg1;
> if (rmtp) {
> - time = ktime_sub(t.timer.expires, t.timer.base->get_time());
> - if (time.tv64 <= 0)
> - return 0;
> - *rmtp = ktime_to_timespec(time);
> + int ret = update_rmtp(&t.timer, rmtp);
> + if (ret <= 0)
> + return ret;
> }
>
> restart->fn = hrtimer_nanosleep_restart;
> @@ -1345,12 +1359,11 @@ long __sched hrtimer_nanosleep_restart(s
> return -ERESTART_RESTARTBLOCK;
> }
>
> -long hrtimer_nanosleep(struct timespec *rqtp, struct timespec *rmtp,
> +long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
> const enum hrtimer_mode mode, const clockid_t clockid)
> {
> struct restart_block *restart;
> struct hrtimer_sleeper t;
> - ktime_t rem;
>
> hrtimer_init(&t.timer, clockid, mode);
> t.timer.expires = timespec_to_ktime(*rqtp);
> @@ -1362,10 +1375,9 @@ long hrtimer_nanosleep(struct timespec *
> return -ERESTARTNOHAND;
>
> if (rmtp) {
> - rem = ktime_sub(t.timer.expires, t.timer.base->get_time());
> - if (rem.tv64 <= 0)
> - return 0;
> - *rmtp = ktime_to_timespec(rem);
> + int ret = update_rmtp(&t.timer, rmtp);
> + if (ret <= 0)
> + return ret;
> }
>
> restart = &current_thread_info()->restart_block;
> @@ -1381,8 +1393,7 @@ long hrtimer_nanosleep(struct timespec *
> asmlinkage long
> sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp)
> {
> - struct timespec tu, rmt;
> - int ret;
> + struct timespec tu;
>
> if (copy_from_user(&tu, rqtp, sizeof(tu)))
> return -EFAULT;
> @@ -1390,15 +1401,7 @@ sys_nanosleep(struct timespec __user *rq
> if (!timespec_valid(&tu))
> return -EINVAL;
>
> - ret = hrtimer_nanosleep(&tu, rmtp ? &rmt : NULL, HRTIMER_MODE_REL,
> - CLOCK_MONOTONIC);
> -
> - if (ret && rmtp) {
> - if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
> - return -EFAULT;
> - }
> -
> - return ret;
> + return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
> }
>
> /*
> --- MM/kernel/posix-timers.c~HRT_RMTP 2008-01-27 17:07:40.000000000 +0300
> +++ MM/kernel/posix-timers.c 2008-02-01 13:18:51.000000000 +0300
> @@ -982,20 +982,10 @@ sys_clock_getres(const clockid_t which_c
> static int common_nsleep(const clockid_t which_clock, int flags,
> struct timespec *tsave, struct timespec __user *rmtp)
> {
> - struct timespec rmt;
> - int ret;
> -
> - ret = hrtimer_nanosleep(tsave, rmtp ? &rmt : NULL,
> + return hrtimer_nanosleep(tsave, rmtp,
> flags & TIMER_ABSTIME ?
> - HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
> + HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
> which_clock);
> -
> - if (ret && rmtp) {
> - if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
> - return -EFAULT;
> - }
> -
> - return ret;
> }
>
> asmlinkage long
>

2008-02-01 15:48:46

by Oleg Nesterov

[permalink] [raw]
Subject: Re: [PATCH 2/5] hrtimer_nanosleep: fix *rmtp handling

On 02/01, Thomas Gleixner wrote:
>
> On Fri, 1 Feb 2008, Oleg Nesterov wrote:
>
> > (Andrew, the same patch, but re-diffed without the first one in series).
>
> I pick them up and feed them through hrtimer.git, once all bugs are
> shaken out :)

Great, thanks.

Thomas, please wait a bit, I'll resend patches 3 and 5.

"PATCH 3/5" also suffers from the buggy "PATCH 1/5", and 5/5 should be
re-diffed.

Sorry to all for the noise.

Oleg.

2008-02-01 18:20:45

by Andrew Morton

[permalink] [raw]
Subject: Re: [PATCH 2/5] hrtimer_nanosleep: fix *rmtp handling

On Fri, 1 Feb 2008 16:16:50 +0100 (CET) Thomas Gleixner <[email protected]> wrote:

> On Fri, 1 Feb 2008, Oleg Nesterov wrote:
>
> > (Andrew, the same patch, but re-diffed without the first one in series).
>
> I pick them up and feed them through hrtimer.git, once all bugs are
> shaken out :)

Please remember that
git+ssh://master.kernel.org/pub/scm/linux/kernel/git/tglx/linux-2.6-hrt.git#mm
contains the "hrtimers: use hrtimers so that msleep() sleeps for the
requested time" patch which kills my USB setup.