From 2a86ac30a6687e47436e547deadae3bf0fc28697 Mon Sep 17 00:00:00 2001 From: "Masami Hiramatsu (Google)" Date: Sun, 24 Sep 2023 22:36:11 +0900 Subject: [PATCH 1/2] Documentation: probes: Add a new ret_ip callback parameter Add a new ret_ip callback parameter description. Link: https://lore.kernel.org/all/169556257133.146934.13560704846459957726.stgit@devnote2/ Fixes: cb16330d1274 ("fprobe: Pass return address to the handlers") Signed-off-by: Masami Hiramatsu (Google) Acked-by: Florent Revest --- Documentation/trace/fprobe.rst | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/Documentation/trace/fprobe.rst b/Documentation/trace/fprobe.rst index 7a895514b5379..196f52386aaa8 100644 --- a/Documentation/trace/fprobe.rst +++ b/Documentation/trace/fprobe.rst @@ -91,9 +91,9 @@ The prototype of the entry/exit callback function are as follows: .. code-block:: c - int entry_callback(struct fprobe *fp, unsigned long entry_ip, struct pt_regs *regs, void *entry_data); + int entry_callback(struct fprobe *fp, unsigned long entry_ip, unsigned long ret_ip, struct pt_regs *regs, void *entry_data); - void exit_callback(struct fprobe *fp, unsigned long entry_ip, struct pt_regs *regs, void *entry_data); + void exit_callback(struct fprobe *fp, unsigned long entry_ip, unsigned long ret_ip, struct pt_regs *regs, void *entry_data); Note that the @entry_ip is saved at function entry and passed to exit handler. If the entry callback function returns !0, the corresponding exit callback will be cancelled. @@ -108,6 +108,10 @@ If the entry callback function returns !0, the corresponding exit callback will Note that this may not be the actual entry address of the function but the address where the ftrace is instrumented. +@ret_ip + This is the return address that the traced function will return to, + somewhere in the caller. This can be used at both entry and exit. + @regs This is the `pt_regs` data structure at the entry and exit. Note that the instruction pointer of @regs may be different from the @entry_ip From 700b2b439766e8aab8a7174991198497345bd411 Mon Sep 17 00:00:00 2001 From: "Masami Hiramatsu (Google)" Date: Tue, 17 Oct 2023 08:49:45 +0900 Subject: [PATCH 2/2] fprobe: Fix to ensure the number of active retprobes is not zero The number of active retprobes can be zero but it is not acceptable, so return EINVAL error if detected. Link: https://lore.kernel.org/all/169750018550.186853.11198884812017796410.stgit@devnote2/ Reported-by: wuqiang.matt Closes: https://lore.kernel.org/all/20231016222103.cb9f426edc60220eabd8aa6a@kernel.org/ Fixes: 5b0ab78998e3 ("fprobe: Add exit_handler support") Signed-off-by: Masami Hiramatsu (Google) --- kernel/trace/fprobe.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c index 3b21f40632582..881f90f0cbcfa 100644 --- a/kernel/trace/fprobe.c +++ b/kernel/trace/fprobe.c @@ -189,7 +189,7 @@ static int fprobe_init_rethook(struct fprobe *fp, int num) { int i, size; - if (num < 0) + if (num <= 0) return -EINVAL; if (!fp->exit_handler) { @@ -202,8 +202,8 @@ static int fprobe_init_rethook(struct fprobe *fp, int num) size = fp->nr_maxactive; else size = num * num_possible_cpus() * 2; - if (size < 0) - return -E2BIG; + if (size <= 0) + return -EINVAL; fp->rethook = rethook_alloc((void *)fp, fprobe_exit_handler); if (!fp->rethook)