Messages in this thread Patch in this message | | | Subject | [PATCH 1/2] i386: Disallow kprobes on NMI handlers | From | Fernando Luis Vázquez Cao <> | Date | Thu, 10 Aug 2006 19:36:39 +0900 |
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A kprobe executes IRET early and that could cause NMI recursion and stack corruption.
Note: This problem was originally identified and solved by Andi Kleen in the x86_64 architecture. This patch is an adaption of his patch for i386.
Signed-off-by: Fernando Vazquez <fernando@intellilink.co.jp> ---
diff -urNp linux-2.6.18-rc4-orig/arch/i386/kernel/entry.S linux-2.6.18-rc4/arch/i386/kernel/entry.S --- linux-2.6.18-rc4-orig/arch/i386/kernel/entry.S 2006-08-10 17:24:14.000000000 +0900 +++ linux-2.6.18-rc4/arch/i386/kernel/entry.S 2006-08-10 17:31:55.000000000 +0900 @@ -725,7 +725,7 @@ debug_stack_correct: * 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 diff -urNp linux-2.6.18-rc4-orig/arch/i386/kernel/nmi.c linux-2.6.18-rc4/arch/i386/kernel/nmi.c --- linux-2.6.18-rc4-orig/arch/i386/kernel/nmi.c 2006-08-10 17:24:15.000000000 +0900 +++ linux-2.6.18-rc4/arch/i386/kernel/nmi.c 2006-08-10 17:40:22.000000000 +0900 @@ -579,7 +579,7 @@ EXPORT_SYMBOL(touch_nmi_watchdog); extern void die_nmi(struct pt_regs *, const char *msg); -void nmi_watchdog_tick (struct pt_regs * regs) +void __kprobes nmi_watchdog_tick (struct pt_regs * regs) { /* diff -urNp linux-2.6.18-rc4-orig/arch/i386/kernel/traps.c linux-2.6.18-rc4/arch/i386/kernel/traps.c --- linux-2.6.18-rc4-orig/arch/i386/kernel/traps.c 2006-08-10 17:24:16.000000000 +0900 +++ linux-2.6.18-rc4/arch/i386/kernel/traps.c 2006-08-10 18:16:12.000000000 +0900 @@ -626,7 +626,8 @@ 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. Dazed and confused, but trying " "to continue\n"); @@ -637,7 +638,8 @@ static void mem_parity_error(unsigned ch 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; @@ -653,7 +655,8 @@ static void io_check_error(unsigned char 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 @@ -671,7 +674,7 @@ static void unknown_nmi_error(unsigned c 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) @@ -703,7 +706,7 @@ void die_nmi (struct pt_regs *regs, cons 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; @@ -741,14 +744,14 @@ static void default_do_nmi(struct pt_reg reassert_nmi(); } -static int dummy_nmi_callback(struct pt_regs * regs, int cpu) +static __kprobes int dummy_nmi_callback(struct pt_regs * regs, int cpu) { return 0; } static nmi_callback_t nmi_callback = dummy_nmi_callback; -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;
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