From 72b3fb24713755cf9740b403e95aa67ceedf3509 Mon Sep 17 00:00:00 2001 From: Li Zhong Date: Thu, 29 Mar 2012 16:11:17 -0400 Subject: x86/nmi: Fix page faults by nmiaction if kmemcheck is enabled This patch tries to fix the problem of page fault exception caused by accessing nmiaction structure in nmi if kmemcheck is enabled. If kmemcheck is enabled, the memory allocated through slab are in pages that are marked non-present, so that some checks could be done in the page fault handling code ( e.g. whether the memory is read before written to ). As nmiaction is allocated in this way, so it resides in a non-present page. Then there is a page fault while the nmi code accessing the nmiaction structure, which would then cause a warning by WARN_ON_ONCE(in_nmi()) in kmemcheck_fault(), called by do_page_fault(). This significantly simplifies the code as well, as the whole dynamic allocation dance goes away. v2: as Peter suggested, changed the nmiaction to use static storage. v3: as Peter suggested, use macro to shorten the codes. Also keep the original usage of register_nmi_handler, so users of this call doesn't need change. Tested-by: Seiji Aguchi Fixes: https://lkml.org/lkml/2012/3/2/356 Signed-off-by: Li Zhong [ simplified the wrappers ] Signed-off-by: Don Zickus Cc: Peter Zijlstra Cc: thomas.mingarelli@hp.com Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/1333051877-15755-4-git-send-email-dzickus@redhat.com [ tidied the patch a bit ] Signed-off-by: Ingo Molnar --- arch/x86/include/asm/nmi.h | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) (limited to 'arch/x86/include/asm/nmi.h') diff --git a/arch/x86/include/asm/nmi.h b/arch/x86/include/asm/nmi.h index 07162dfbff84..a1a836c8131c 100644 --- a/arch/x86/include/asm/nmi.h +++ b/arch/x86/include/asm/nmi.h @@ -37,8 +37,24 @@ enum { typedef int (*nmi_handler_t)(unsigned int, struct pt_regs *); -int register_nmi_handler(unsigned int, nmi_handler_t, unsigned long, - const char *); +struct nmiaction { + struct list_head list; + nmi_handler_t handler; + unsigned int flags; + const char *name; +}; + +#define register_nmi_handler(t, fn, fg, n) \ +({ \ + static struct nmiaction fn##_na = { \ + .handler = (fn), \ + .name = (n), \ + .flags = (fg), \ + }; \ + __register_nmi_handler((t), &fn##_na); \ +}) + +int __register_nmi_handler(unsigned int, struct nmiaction *); void unregister_nmi_handler(unsigned int, const char *); -- cgit v1.2.3