| Message ID | 20210223144151.916675-2-zhengyejian1@huawei.com |
|---|---|
| State | New |
| Headers | show |
| Series | [4.9.y,1/1] futex: Fix OWNER_DEAD fixup | expand |
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.net > 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; -- Lee Jones [李琼斯] Senior Technical Lead - Developer Services Linaro.org │ Open source software for Arm SoCs Follow Linaro: Facebook | Twitter | Blog
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.net >> 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.net > > > 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; > > > if (get_futex_value_locked(&uval, uaddr)) > > > goto handle_fault; > > -- Lee Jones [李琼斯] Senior Technical Lead - Developer Services Linaro.org │ Open source software for Arm SoCs Follow Linaro: Facebook | Twitter | Blog
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.net >>>> 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; >>>> if (get_futex_value_locked(&uval, uaddr)) >>>> goto handle_fault; >>> >
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.net > 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
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;