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Message-Id: <20170719175900.124074-1-thgarnie@google.com> Date: Wed, 19 Jul 2017 10:58:58 -0700 From: Thomas Garnier <thgarnie@...gle.com> To: Russell King <linux@...linux.org.uk>, Thomas Garnier <thgarnie@...gle.com>, Thomas Gleixner <tglx@...utronix.de>, Catalin Marinas <catalin.marinas@....com>, Will Deacon <will.deacon@....com>, Dave Martin <Dave.Martin@....com>, Chris Metcalf <cmetcalf@...lanox.com>, Pratyush Anand <panand@...hat.com>, leonard.crestez@....com Cc: linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org, kernel-hardening@...ts.openwall.com Subject: [PATCH 1/3] arm/syscalls: Move address limit check in loop The work pending loop can call set_fs after addr_limit_user_check removed the _TIF_FSCHECK flag. To prevent the infinite loop, move the addr_limit_user_check call at the beginning of the loop. Fixes: 73ac5d6a2b6a ("arm/syscalls: Check address limit on user-mode return") Reported-by: Leonard Crestez <leonard.crestez@....com> Signed-off-by: Thomas Garnier <thgarnie@...gle.com> --- arch/arm/kernel/signal.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c index 3a48b54c6405..f4574287d14b 100644 --- a/arch/arm/kernel/signal.c +++ b/arch/arm/kernel/signal.c @@ -573,10 +573,10 @@ do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall) */ trace_hardirqs_off(); - /* Check valid user FS if needed */ - addr_limit_user_check(); - do { + /* Check valid user FS if needed */ + addr_limit_user_check(); + if (likely(thread_flags & _TIF_NEED_RESCHED)) { schedule(); } else { -- 2.14.0.rc0.284.gd933b75aa4-goog
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