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| author | Masami Hiramatsu (Google) <mhiramat@kernel.org> | 2022-11-30 22:33:09 +0900 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2023-01-07 12:29:08 +0100 |
| commit | 8e791f7eba4c7711f56616ae163ee3cbc00b1bf4 (patch) | |
| tree | 6b0f284c9a0ecbec630373238f79d0ad30c9e088 /arch/x86/kernel/kprobes | |
| parent | 03c4c7f88709fac0e20b6a48357c73d6fc50e544 (diff) | |
| download | lwn-8e791f7eba4c7711f56616ae163ee3cbc00b1bf4.tar.gz lwn-8e791f7eba4c7711f56616ae163ee3cbc00b1bf4.zip | |
x86/kprobes: Drop removed INT3 handling code
Drop removed INT3 handling code from kprobe_int3_handler() because this
case (get_kprobe() doesn't return corresponding kprobe AND the INT3 is
removed) must not happen with the kprobe managed INT3, but can happen
with the non-kprobe INT3, which should be handled by other callbacks.
For the kprobe managed INT3, it is already safe. The commit 5c02ece81848d
("x86/kprobes: Fix ordering while text-patching") introduced
text_poke_sync() to the arch_disarm_kprobe() right after removing INT3.
Since this text_poke_sync() uses IPI to call sync_core() on all online
cpus, that ensures that all running INT3 exception handlers have done.
And, the unregister_kprobe() will remove the kprobe from the hash table
after arch_disarm_kprobe().
Thus, when the kprobe managed INT3 hits, kprobe_int3_handler() should
be able to find corresponding kprobe always by get_kprobe(). If it can
not find any kprobe, this means that is NOT a kprobe managed INT3.
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/166981518895.1131462.4693062055762912734.stgit@devnote3
Diffstat (limited to 'arch/x86/kernel/kprobes')
| -rw-r--r-- | arch/x86/kernel/kprobes/core.c | 14 |
1 files changed, 0 insertions, 14 deletions
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 66299682b6b7..33390ed4dcf3 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -986,20 +986,6 @@ int kprobe_int3_handler(struct pt_regs *regs) kprobe_post_process(p, regs, kcb); return 1; } - } - - if (*addr != INT3_INSN_OPCODE) { - /* - * The breakpoint instruction was removed right - * after we hit it. Another cpu has removed - * either a probepoint or a debugger breakpoint - * at this address. In either case, no further - * handling of this interrupt is appropriate. - * Back up over the (now missing) int3 and run - * the original instruction. - */ - regs->ip = (unsigned long)addr; - return 1; } /* else: not a kprobe fault; let the kernel handle it */ return 0; |