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authorMasami Hiramatsu <mhiramat@kernel.org>2021-09-14 23:42:51 +0900
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2021-09-30 21:24:08 -0400
commitbf094cffea2a6503ce84062f9f0243bef77c58f9 (patch)
treec7e59457f4ff4311b54ad508396d9c21170a57cf /kernel/kprobes.c
parent7da89495d500d6a1e6fe1019587c3b611c7bd217 (diff)
x86/kprobes: Fixup return address in generic trampoline handler
In x86, the fake return address on the stack saved by __kretprobe_trampoline() will be replaced with the real return address after returning from trampoline_handler(). Before fixing the return address, the real return address can be found in the 'current->kretprobe_instances'. However, since there is a window between updating the 'current->kretprobe_instances' and fixing the address on the stack, if an interrupt happens at that timing and the interrupt handler does stacktrace, it may fail to unwind because it can not get the correct return address from 'current->kretprobe_instances'. This will eliminate that window by fixing the return address right before updating 'current->kretprobe_instances'. Link: https://lkml.kernel.org/r/163163057094.489837.9044470370440745866.stgit@devnote2 Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Tested-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/kprobes.c')
-rw-r--r--kernel/kprobes.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index ebc587b9a346..b62af9fc3607 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1922,6 +1922,15 @@ unsigned long kretprobe_find_ret_addr(struct task_struct *tsk, void *fp,
}
NOKPROBE_SYMBOL(kretprobe_find_ret_addr);
+void __weak arch_kretprobe_fixup_return(struct pt_regs *regs,
+ kprobe_opcode_t *correct_ret_addr)
+{
+ /*
+ * Do nothing by default. Please fill this to update the fake return
+ * address on the stack with the correct one on each arch if possible.
+ */
+}
+
unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
void *frame_pointer)
{
@@ -1967,6 +1976,8 @@ unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
first = first->next;
}
+ arch_kretprobe_fixup_return(regs, correct_ret_addr);
+
/* Unlink all nodes for this frame. */
first = current->kretprobe_instances.first;
current->kretprobe_instances.first = node->next;