From a00e817f42663941ea0aa5f85a9d1c4f8b212839 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Tue, 8 Sep 2009 12:47:55 -0400 Subject: [PATCH] kprobes/x86-32: Move irq-exit functions to kprobes section Move irq-exit functions to .kprobes.text section to protect against kprobes recursion. When I ran kprobe stress test on x86-32, I found below symbols cause unrecoverable recursive probing: ret_from_exception ret_from_intr check_userspace restore_all restore_all_notrace restore_nocheck irq_return And also, I found some interrupt/exception entry points that cause similar problems. This patch moves those symbols (including their container functions) to .kprobes.text section to prevent any kprobes probing. Signed-off-by: Masami Hiramatsu Cc: Frederic Weisbecker Cc: Ananth N Mavinakayanahalli Cc: Jim Keniston Cc: Ingo Molnar LKML-Reference: <20090908164755.24050.81182.stgit@dhcp-100-2-132.bos.redhat.com> Signed-off-by: Frederic Weisbecker --- arch/x86/kernel/entry_32.S | 24 ++++++++++++++++++++++++ kernel/kprobes.c | 2 ++ 2 files changed, 26 insertions(+) diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S index c097e7d607c6..beb30da203d6 100644 --- a/arch/x86/kernel/entry_32.S +++ b/arch/x86/kernel/entry_32.S @@ -333,6 +333,10 @@ ENTRY(ret_from_fork) CFI_ENDPROC END(ret_from_fork) +/* + * Interrupt exit functions should be protected against kprobes + */ + .pushsection .kprobes.text, "ax" /* * Return to user mode is not as complex as all this looks, * but we want the default path for a system call return to @@ -383,6 +387,10 @@ need_resched: END(resume_kernel) #endif CFI_ENDPROC +/* + * End of kprobes section + */ + .popsection /* SYSENTER_RETURN points to after the "sysenter" instruction in the vsyscall page. See vsyscall-sysentry.S, which defines the symbol. */ @@ -513,6 +521,10 @@ sysexit_audit: PTGS_TO_GS_EX ENDPROC(ia32_sysenter_target) +/* + * syscall stub including irq exit should be protected against kprobes + */ + .pushsection .kprobes.text, "ax" # system call handler stub ENTRY(system_call) RING0_INT_FRAME # can't unwind into user space anyway @@ -705,6 +717,10 @@ syscall_badsys: jmp resume_userspace END(syscall_badsys) CFI_ENDPROC +/* + * End of kprobes section + */ + .popsection /* * System calls that need a pt_regs pointer. @@ -814,6 +830,10 @@ common_interrupt: ENDPROC(common_interrupt) CFI_ENDPROC +/* + * Irq entries should be protected against kprobes + */ + .pushsection .kprobes.text, "ax" #define BUILD_INTERRUPT3(name, nr, fn) \ ENTRY(name) \ RING0_INT_FRAME; \ @@ -980,6 +1000,10 @@ ENTRY(spurious_interrupt_bug) jmp error_code CFI_ENDPROC END(spurious_interrupt_bug) +/* + * End of kprobes section + */ + .popsection ENTRY(kernel_thread_helper) pushl $0 # fake return address for unwinder diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 3267d90bc9d6..00d01b0f9fee 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -91,6 +91,8 @@ static spinlock_t *kretprobe_table_lock_ptr(unsigned long hash) static struct kprobe_blackpoint kprobe_blacklist[] = { {"preempt_schedule",}, {"native_get_debugreg",}, + {"irq_entries_start",}, + {"common_interrupt",}, {NULL} /* Terminator */ }; -- 2.39.2