[PATCH 4.9.y 0/1] Bugfix for 781691c797de ("futex: Avoid violating the 10th rule of futex")
This patch may fix the following bug:
Link: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/?h=lin...
> static int __fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q, > struct task_struct *argowner) > { > struct futex_pi_state *pi_state = q->pi_state; > struct task_struct *oldowner, *newowner; > u32 uval, curval, newval, newtid; > int err = 0; > > oldowner = pi_state->owner; > > /* Owner died? */ > if (!pi_state->owner) > newtid |= FUTEX_OWNER_DIED; Variable "newtid" is used without initialized.
Peter Zijlstra (1): futex: Fix OWNER_DEAD fixup
kernel/futex.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
From: Peter Zijlstra peterz@infradead.org
commit a97cb0e7b3f4c6297fd857055ae8e895f402f501 upstream.
Both Geert and DaveJ reported that the recent futex commit:
c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex")
introduced a problem with setting OWNER_DEAD. We set the bit on an uninitialized variable and then entirely optimize it away as a dead-store.
Move the setting of the bit to where it is more useful.
Reported-by: Geert Uytterhoeven geert@linux-m68k.org Reported-by: Dave Jones davej@codemonkey.org.uk Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Cc: Andrew Morton akpm@linux-foundation.org Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Paul E. McKenney paulmck@us.ibm.com Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Fixes: c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex") Link: http://lkml.kernel.org/r/20180122103947.GD2228@hirez.programming.kicks-ass.n... Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Zheng Yejian zhengyejian1@huawei.com --- kernel/futex.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/futex.c b/kernel/futex.c index b65dbb5d60bb..604d1cb9839d 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -2424,9 +2424,6 @@ static int __fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q, int err = 0;
oldowner = pi_state->owner; - /* Owner died? */ - if (!pi_state->owner) - newtid |= FUTEX_OWNER_DIED;
/* * We are here because either: @@ -2484,6 +2481,9 @@ static int __fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q, }
newtid = task_pid_vnr(newowner) | FUTEX_WAITERS; + /* Owner died? */ + if (!pi_state->owner) + newtid |= FUTEX_OWNER_DIED;
if (get_futex_value_locked(&uval, uaddr)) goto handle_fault;
On Tue, 23 Feb 2021, Zheng Yejian wrote:
From: Peter Zijlstra peterz@infradead.org
commit a97cb0e7b3f4c6297fd857055ae8e895f402f501 upstream.
Both Geert and DaveJ reported that the recent futex commit:
c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex")
introduced a problem with setting OWNER_DEAD. We set the bit on an uninitialized variable and then entirely optimize it away as a dead-store.
Move the setting of the bit to where it is more useful.
Reported-by: Geert Uytterhoeven geert@linux-m68k.org Reported-by: Dave Jones davej@codemonkey.org.uk Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Cc: Andrew Morton akpm@linux-foundation.org Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Paul E. McKenney paulmck@us.ibm.com Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Fixes: c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex") Link: http://lkml.kernel.org/r/20180122103947.GD2228@hirez.programming.kicks-ass.n... Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Zheng Yejian zhengyejian1@huawei.com
Why have you dropped my Reviewed-by?
kernel/futex.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/futex.c b/kernel/futex.c index b65dbb5d60bb..604d1cb9839d 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -2424,9 +2424,6 @@ static int __fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q, int err = 0; oldowner = pi_state->owner;
- /* Owner died? */
- if (!pi_state->owner)
newtid |= FUTEX_OWNER_DIED;/* * We are here because either: @@ -2484,6 +2481,9 @@ static int __fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q, } newtid = task_pid_vnr(newowner) | FUTEX_WAITERS;
- /* Owner died? */
- if (!pi_state->owner)
newtid |= FUTEX_OWNER_DIED;if (get_futex_value_locked(&uval, uaddr)) goto handle_fault;
On 2021/2/24 19:19, Lee Jones wrote:
On Tue, 23 Feb 2021, Zheng Yejian wrote:
From: Peter Zijlstra peterz@infradead.org
commit a97cb0e7b3f4c6297fd857055ae8e895f402f501 upstream.
Both Geert and DaveJ reported that the recent futex commit:
c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex")
introduced a problem with setting OWNER_DEAD. We set the bit on an uninitialized variable and then entirely optimize it away as a dead-store.
Move the setting of the bit to where it is more useful.
Reported-by: Geert Uytterhoeven geert@linux-m68k.org Reported-by: Dave Jones davej@codemonkey.org.uk Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Cc: Andrew Morton akpm@linux-foundation.org Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Paul E. McKenney paulmck@us.ibm.com Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Fixes: c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex") Link: http://lkml.kernel.org/r/20180122103947.GD2228@hirez.programming.kicks-ass.n... Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Zheng Yejian zhengyejian1@huawei.com
Why have you dropped my Reviewed-by?
Really sorry. I thought that a changed patchset needs another review. Then I do need to append your Reviewed-by and send a "V2" patchset, Do I?
kernel/futex.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/futex.c b/kernel/futex.c index b65dbb5d60bb..604d1cb9839d 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -2424,9 +2424,6 @@ static int __fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q, int err = 0; oldowner = pi_state->owner;
- /* Owner died? */
- if (!pi_state->owner)
newtid |= FUTEX_OWNER_DIED;/* * We are here because either: @@ -2484,6 +2481,9 @@ static int __fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q, } newtid = task_pid_vnr(newowner) | FUTEX_WAITERS;
- /* Owner died? */
- if (!pi_state->owner)
newtid |= FUTEX_OWNER_DIED;if (get_futex_value_locked(&uval, uaddr)) goto handle_fault;
On Thu, 25 Feb 2021, Zhengyejian (Zetta) wrote:
On 2021/2/24 19:19, Lee Jones wrote:
On Tue, 23 Feb 2021, Zheng Yejian wrote:
From: Peter Zijlstra peterz@infradead.org
commit a97cb0e7b3f4c6297fd857055ae8e895f402f501 upstream.
Both Geert and DaveJ reported that the recent futex commit:
c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex")
introduced a problem with setting OWNER_DEAD. We set the bit on an uninitialized variable and then entirely optimize it away as a dead-store.
Move the setting of the bit to where it is more useful.
Reported-by: Geert Uytterhoeven geert@linux-m68k.org Reported-by: Dave Jones davej@codemonkey.org.uk Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Cc: Andrew Morton akpm@linux-foundation.org Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Paul E. McKenney paulmck@us.ibm.com Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Fixes: c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex") Link: http://lkml.kernel.org/r/20180122103947.GD2228@hirez.programming.kicks-ass.n... Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Zheng Yejian zhengyejian1@huawei.com
Why have you dropped my Reviewed-by?
Really sorry. I thought that a changed patchset needs another review. Then I do need to append your Reviewed-by and send a "V2" patchset, Do I?
No need. I won't hold up merging just for that.
Just bear in mind that you should apply and carry forward *-by tags unless there have been significant/functional changes.
Reviewed-by: Lee Jones lee.jones@linaro.org
kernel/futex.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/futex.c b/kernel/futex.c index b65dbb5d60bb..604d1cb9839d 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -2424,9 +2424,6 @@ static int __fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q, int err = 0; oldowner = pi_state->owner;
- /* Owner died? */
- if (!pi_state->owner)
newtid |= FUTEX_OWNER_DIED;
- We are here because either:
@@ -2484,6 +2481,9 @@ static int __fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q, } newtid = task_pid_vnr(newowner) | FUTEX_WAITERS;
- /* Owner died? */
- if (!pi_state->owner)
newtid |= FUTEX_OWNER_DIED;
On 2021/2/25 16:09, Lee Jones wrote:
On Thu, 25 Feb 2021, Zhengyejian (Zetta) wrote:
On 2021/2/24 19:19, Lee Jones wrote:
On Tue, 23 Feb 2021, Zheng Yejian wrote:
From: Peter Zijlstra peterz@infradead.org
commit a97cb0e7b3f4c6297fd857055ae8e895f402f501 upstream.
Both Geert and DaveJ reported that the recent futex commit:
c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex")introduced a problem with setting OWNER_DEAD. We set the bit on an uninitialized variable and then entirely optimize it away as a dead-store.
Move the setting of the bit to where it is more useful.
Reported-by: Geert Uytterhoeven geert@linux-m68k.org Reported-by: Dave Jones davej@codemonkey.org.uk Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Cc: Andrew Morton akpm@linux-foundation.org Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Paul E. McKenney paulmck@us.ibm.com Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Fixes: c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex") Link: http://lkml.kernel.org/r/20180122103947.GD2228@hirez.programming.kicks-ass.n... Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Zheng Yejian zhengyejian1@huawei.com
Why have you dropped my Reviewed-by?
Really sorry. I thought that a changed patchset needs another review. Then I do need to append your Reviewed-by and send a "V2" patchset, Do I?
No need. I won't hold up merging just for that.
Just bear in mind that you should apply and carry forward *-by tags unless there have been significant/functional changes.
Reviewed-by: Lee Jones lee.jones@linaro.org
I get it, thanks.
kernel/futex.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/futex.c b/kernel/futex.c index b65dbb5d60bb..604d1cb9839d 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -2424,9 +2424,6 @@ static int __fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q, int err = 0; oldowner = pi_state->owner;
- /* Owner died? */
- if (!pi_state->owner)
newtid |= FUTEX_OWNER_DIED;
- We are here because either:
@@ -2484,6 +2481,9 @@ static int __fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q, } newtid = task_pid_vnr(newowner) | FUTEX_WAITERS;
- /* Owner died? */
- if (!pi_state->owner)
newtid |= FUTEX_OWNER_DIED;
On Tue, Feb 23, 2021 at 10:41:51PM +0800, Zheng Yejian wrote:
From: Peter Zijlstra peterz@infradead.org
commit a97cb0e7b3f4c6297fd857055ae8e895f402f501 upstream.
Both Geert and DaveJ reported that the recent futex commit:
c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex")
introduced a problem with setting OWNER_DEAD. We set the bit on an uninitialized variable and then entirely optimize it away as a dead-store.
Move the setting of the bit to where it is more useful.
Reported-by: Geert Uytterhoeven geert@linux-m68k.org Reported-by: Dave Jones davej@codemonkey.org.uk Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Cc: Andrew Morton akpm@linux-foundation.org Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Paul E. McKenney paulmck@us.ibm.com Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Fixes: c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex") Link: http://lkml.kernel.org/r/20180122103947.GD2228@hirez.programming.kicks-ass.n... Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Zheng Yejian zhengyejian1@huawei.com
kernel/futex.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
Now queued up, thanks.
greg k-h
linux-stable-mirror@lists.linaro.org
-
Greg KH -
Lee Jones -
Zheng Yejian -
Zhengyejian (Zetta)