From 7c4788950ba5922fde976d80b72baf46f14dee8d Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 22 Nov 2016 10:57:15 +0100 Subject: x86/uaccess, sched/preempt: Verify access_ok() context I recently encountered wreckage because access_ok() was used where it should not be, add an explicit WARN when access_ok() is used wrongly. Signed-off-by: Peter Zijlstra (Intel) Cc: Andy Lutomirski Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- arch/x86/include/asm/uaccess.h | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) (limited to 'arch/x86/include/asm/uaccess.h') diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index faf3687f1035..ea148313570f 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -68,6 +68,12 @@ static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size, un __chk_range_not_ok((unsigned long __force)(addr), size, limit); \ }) +#ifdef CONFIG_DEBUG_ATOMIC_SLEEP +# define WARN_ON_IN_IRQ() WARN_ON_ONCE(!in_task()) +#else +# define WARN_ON_IN_IRQ() +#endif + /** * access_ok: - Checks if a user space pointer is valid * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that @@ -88,8 +94,11 @@ static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size, un * checks that the pointer is in the user space range - after calling * this function, memory access functions may still return -EFAULT. */ -#define access_ok(type, addr, size) \ - likely(!__range_not_ok(addr, size, user_addr_max())) +#define access_ok(type, addr, size) \ +({ \ + WARN_ON_IN_IRQ(); \ + likely(!__range_not_ok(addr, size, user_addr_max())); \ +}) /* * These are the main single-value transfer routines. They automatically -- cgit v1.2.3