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kprobes/x86-32: Move irq-exit functions to kprobes section

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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 <mhiramat@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <20090908164755.24050.81182.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
This commit is contained in:
Masami Hiramatsu 2009-09-08 12:47:55 -04:00 committed by Frederic Weisbecker
parent f12b4f546b
commit a00e817f42
2 changed files with 26 additions and 0 deletions
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24
arch/x86/kernel/entry_32.S
View file

@ -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

2
kernel/kprobes.c
View file

@ -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 */
};