From 06039754d775d3e48e4a292e4f353321205eff53 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Fernando=20Luis=20V=E1zquez=20Cao?= Date: Tue, 26 Sep 2006 10:52:36 +0200 Subject: [PATCH] [PATCH] i386: Disallow kprobes on NMI handlers A kprobe executes IRET early and that could cause NMI recursion and stack corruption. Note: This problem was originally spotted and solved by Andi Kleen in the x86_64 architecture. This patch is an adaption of his patch for i386. AK: Merged with current code which was a bit different. AK: Removed printk in nmi handler that shouldn't be there in the first time AK: Added missing include. AK: added KPROBES_END Signed-off-by: Fernando Vazquez Signed-off-by: Andi Kleen --- arch/i386/kernel/entry.S | 3 ++- arch/i386/kernel/nmi.c | 6 +++--- arch/i386/kernel/traps.c | 15 +++++++++------ 3 files changed, 14 insertions(+), 10 deletions(-) diff --git a/arch/i386/kernel/entry.S b/arch/i386/kernel/entry.S index dede506..0928f70 100644 --- a/arch/i386/kernel/entry.S +++ b/arch/i386/kernel/entry.S @@ -729,7 +729,7 @@ KPROBE_END(debug) * check whether we got an NMI on the debug path where the debug * fault happened on the sysenter path. */ -ENTRY(nmi) +KPROBE_ENTRY(nmi) RING0_INT_FRAME pushl %eax CFI_ADJUST_CFA_OFFSET 4 @@ -805,6 +805,7 @@ nmi_16bit_stack: .align 4 .long 1b,iret_exc .previous +KPROBE_END(nmi) KPROBE_ENTRY(int3) RING0_INT_FRAME diff --git a/arch/i386/kernel/nmi.c b/arch/i386/kernel/nmi.c index 7b9a053..dbda706 100644 --- a/arch/i386/kernel/nmi.c +++ b/arch/i386/kernel/nmi.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include @@ -882,7 +883,7 @@ EXPORT_SYMBOL(touch_nmi_watchdog); extern void die_nmi(struct pt_regs *, const char *msg); -int nmi_watchdog_tick (struct pt_regs * regs, unsigned reason) +__kprobes int nmi_watchdog_tick(struct pt_regs * regs, unsigned reason) { /* @@ -962,8 +963,7 @@ int nmi_watchdog_tick (struct pt_regs * regs, unsigned reason) * This matches the old behaviour. */ rc = 1; - } else - printk(KERN_WARNING "Unknown enabled NMI hardware?!\n"); + } } done: return rc; diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c index 00d643f..5c0f496 100644 --- a/arch/i386/kernel/traps.c +++ b/arch/i386/kernel/traps.c @@ -689,7 +689,8 @@ gp_in_kernel: } } -static void mem_parity_error(unsigned char reason, struct pt_regs * regs) +static __kprobes void +mem_parity_error(unsigned char reason, struct pt_regs * regs) { printk(KERN_EMERG "Uhhuh. NMI received for unknown reason %02x on " "CPU %d.\n", reason, smp_processor_id()); @@ -704,7 +705,8 @@ static void mem_parity_error(unsigned char reason, struct pt_regs * regs) clear_mem_error(reason); } -static void io_check_error(unsigned char reason, struct pt_regs * regs) +static __kprobes void +io_check_error(unsigned char reason, struct pt_regs * regs) { unsigned long i; @@ -720,7 +722,8 @@ static void io_check_error(unsigned char reason, struct pt_regs * regs) outb(reason, 0x61); } -static void unknown_nmi_error(unsigned char reason, struct pt_regs * regs) +static __kprobes void +unknown_nmi_error(unsigned char reason, struct pt_regs * regs) { #ifdef CONFIG_MCA /* Might actually be able to figure out what the guilty party @@ -741,7 +744,7 @@ static void unknown_nmi_error(unsigned char reason, struct pt_regs * regs) static DEFINE_SPINLOCK(nmi_print_lock); -void die_nmi (struct pt_regs *regs, const char *msg) +void __kprobes die_nmi(struct pt_regs *regs, const char *msg) { if (notify_die(DIE_NMIWATCHDOG, msg, regs, 0, 2, SIGINT) == NOTIFY_STOP) @@ -773,7 +776,7 @@ void die_nmi (struct pt_regs *regs, const char *msg) do_exit(SIGSEGV); } -static void default_do_nmi(struct pt_regs * regs) +static __kprobes void default_do_nmi(struct pt_regs * regs) { unsigned char reason = 0; @@ -811,7 +814,7 @@ static void default_do_nmi(struct pt_regs * regs) reassert_nmi(); } -fastcall void do_nmi(struct pt_regs * regs, long error_code) +fastcall __kprobes void do_nmi(struct pt_regs * regs, long error_code) { int cpu; -- 1.9.1