lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Mon, 2 May 2016 17:10:44 -0700 From: Greg Kroah-Hartman <gregkh@...uxfoundation.org> To: linux-kernel@...r.kernel.org Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>, stable@...r.kernel.org, Romain Perier <romain.perier@...e-electrons.com>, linux-arch@...r.kernel.org, Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>, Arnd Bergmann <arnd@...db.de>, Peter Zijlstra <peterz@...radead.org>, Thomas Gleixner <tglx@...utronix.de> Subject: [PATCH 4.5 045/200] asm-generic/futex: Re-enable preemption in futex_atomic_cmpxchg_inatomic() 4.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Romain Perier <romain.perier@...e-electrons.com> commit fba7cd681b6155e2d93e7862fcd6f970336b83c3 upstream. The recent decoupling of pagefault disable and preempt disable added an explicit preempt_disable/enable() pair to the futex_atomic_cmpxchg_inatomic() implementation in asm-generic/futex.h. But it forgot to add preempt_enable() calls to the error handling code pathes, which results in a preemption count imbalance. This is observable on boot when the test for atomic_cmpxchg() is calling futex_atomic_cmpxchg_inatomic() on a NULL pointer. Add the missing preempt_enable() calls to the error handling code pathes. [ tglx: Massaged changelog ] Fixes: d9b9ff8c1889 ("sched/preempt, futex: Disable preemption in UP futex_atomic_cmpxchg_inatomic() explicitly") Signed-off-by: Romain Perier <romain.perier@...e-electrons.com> Cc: linux-arch@...r.kernel.org Cc: Thomas Petazzoni <thomas.petazzoni@...e-electrons.com> Cc: Arnd Bergmann <arnd@...db.de> Cc: Peter Zijlstra <peterz@...radead.org> Link: http://lkml.kernel.org/r/1460640963-690-1-git-send-email-romain.perier@free-electrons.com Signed-off-by: Thomas Gleixner <tglx@...utronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org> --- include/asm-generic/futex.h | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/include/asm-generic/futex.h +++ b/include/asm-generic/futex.h @@ -108,11 +108,15 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 val; preempt_disable(); - if (unlikely(get_user(val, uaddr) != 0)) + if (unlikely(get_user(val, uaddr) != 0)) { + preempt_enable(); return -EFAULT; + } - if (val == oldval && unlikely(put_user(newval, uaddr) != 0)) + if (val == oldval && unlikely(put_user(newval, uaddr) != 0)) { + preempt_enable(); return -EFAULT; + } *uval = val; preempt_enable();
Powered by blists - more mailing lists