6.1-stable review patch. If anyone has any objections, please let me know.
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From: Masami Hiramatsu (Google) mhiramat@kernel.org
[ Upstream commit 76d0de5729c0569c4071e7f21fcab394e502f03a ]
Pass the private entry_data to the entry and exit handlers so that they can share the context data, something like saved function arguments etc. User must specify the private entry_data size by @entry_data_size field before registering the fprobe.
Link: https://lkml.kernel.org/r/167526696173.433354.17408372048319432574.stgit@mhi...
Cc: Florent Revest revest@chromium.org Cc: Mark Rutland mark.rutland@arm.com Cc: Will Deacon will@kernel.org Signed-off-by: Masami Hiramatsu (Google) mhiramat@kernel.org Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org Stable-dep-of: 700b2b439766 ("fprobe: Fix to ensure the number of active retprobes is not zero") Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/fprobe.h | 8 ++++++-- kernel/trace/bpf_trace.c | 2 +- kernel/trace/fprobe.c | 21 ++++++++++++++------- lib/test_fprobe.c | 6 ++++-- samples/fprobe/fprobe_example.c | 6 ++++-- 5 files changed, 29 insertions(+), 14 deletions(-)
diff --git a/include/linux/fprobe.h b/include/linux/fprobe.h index 1c2bde0ead736..e0d4e61362491 100644 --- a/include/linux/fprobe.h +++ b/include/linux/fprobe.h @@ -13,6 +13,7 @@ * @nmissed: The counter for missing events. * @flags: The status flag. * @rethook: The rethook data structure. (internal data) + * @entry_data_size: The private data storage size. * @entry_handler: The callback function for function entry. * @exit_handler: The callback function for function exit. */ @@ -29,9 +30,12 @@ struct fprobe { unsigned long nmissed; unsigned int flags; struct rethook *rethook; + size_t entry_data_size;
- void (*entry_handler)(struct fprobe *fp, unsigned long entry_ip, struct pt_regs *regs); - void (*exit_handler)(struct fprobe *fp, unsigned long entry_ip, struct pt_regs *regs); + void (*entry_handler)(struct fprobe *fp, unsigned long entry_ip, + struct pt_regs *regs, void *entry_data); + void (*exit_handler)(struct fprobe *fp, unsigned long entry_ip, + struct pt_regs *regs, void *entry_data); };
/* This fprobe is soft-disabled. */ diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 8c77c54e6348b..f4a494a457c52 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -2646,7 +2646,7 @@ kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link,
static void kprobe_multi_link_handler(struct fprobe *fp, unsigned long fentry_ip, - struct pt_regs *regs) + struct pt_regs *regs, void *data) { struct bpf_kprobe_multi_link *link;
diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c index 1322247ce6488..be28d1bc84e80 100644 --- a/kernel/trace/fprobe.c +++ b/kernel/trace/fprobe.c @@ -17,14 +17,16 @@ struct fprobe_rethook_node { struct rethook_node node; unsigned long entry_ip; + char data[]; };
static void fprobe_handler(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *ops, struct ftrace_regs *fregs) { struct fprobe_rethook_node *fpr; - struct rethook_node *rh; + struct rethook_node *rh = NULL; struct fprobe *fp; + void *entry_data = NULL; int bit;
fp = container_of(ops, struct fprobe, ops); @@ -37,9 +39,6 @@ static void fprobe_handler(unsigned long ip, unsigned long parent_ip, return; }
- if (fp->entry_handler) - fp->entry_handler(fp, ip, ftrace_get_regs(fregs)); - if (fp->exit_handler) { rh = rethook_try_get(fp->rethook); if (!rh) { @@ -48,9 +47,16 @@ static void fprobe_handler(unsigned long ip, unsigned long parent_ip, } fpr = container_of(rh, struct fprobe_rethook_node, node); fpr->entry_ip = ip; - rethook_hook(rh, ftrace_get_regs(fregs), true); + if (fp->entry_data_size) + entry_data = fpr->data; }
+ if (fp->entry_handler) + fp->entry_handler(fp, ip, ftrace_get_regs(fregs), entry_data); + + if (rh) + rethook_hook(rh, ftrace_get_regs(fregs), true); + out: ftrace_test_recursion_unlock(bit); } @@ -81,7 +87,8 @@ static void fprobe_exit_handler(struct rethook_node *rh, void *data,
fpr = container_of(rh, struct fprobe_rethook_node, node);
- fp->exit_handler(fp, fpr->entry_ip, regs); + fp->exit_handler(fp, fpr->entry_ip, regs, + fp->entry_data_size ? (void *)fpr->data : NULL); } NOKPROBE_SYMBOL(fprobe_exit_handler);
@@ -146,7 +153,7 @@ static int fprobe_init_rethook(struct fprobe *fp, int num) for (i = 0; i < size; i++) { struct fprobe_rethook_node *node;
- node = kzalloc(sizeof(*node), GFP_KERNEL); + node = kzalloc(sizeof(*node) + fp->entry_data_size, GFP_KERNEL); if (!node) { rethook_free(fp->rethook); fp->rethook = NULL; diff --git a/lib/test_fprobe.c b/lib/test_fprobe.c index e0381b3ec410c..34fa5a5bbda1f 100644 --- a/lib/test_fprobe.c +++ b/lib/test_fprobe.c @@ -30,7 +30,8 @@ static noinline u32 fprobe_selftest_target2(u32 value) return (value / div_factor) + 1; }
-static notrace void fp_entry_handler(struct fprobe *fp, unsigned long ip, struct pt_regs *regs) +static notrace void fp_entry_handler(struct fprobe *fp, unsigned long ip, + struct pt_regs *regs, void *data) { KUNIT_EXPECT_FALSE(current_test, preemptible()); /* This can be called on the fprobe_selftest_target and the fprobe_selftest_target2 */ @@ -39,7 +40,8 @@ static notrace void fp_entry_handler(struct fprobe *fp, unsigned long ip, struct entry_val = (rand1 / div_factor); }
-static notrace void fp_exit_handler(struct fprobe *fp, unsigned long ip, struct pt_regs *regs) +static notrace void fp_exit_handler(struct fprobe *fp, unsigned long ip, + struct pt_regs *regs, void *data) { unsigned long ret = regs_return_value(regs);
diff --git a/samples/fprobe/fprobe_example.c b/samples/fprobe/fprobe_example.c index e22da8573116e..dd794990ad7ec 100644 --- a/samples/fprobe/fprobe_example.c +++ b/samples/fprobe/fprobe_example.c @@ -48,7 +48,8 @@ static void show_backtrace(void) stack_trace_print(stacks, len, 24); }
-static void sample_entry_handler(struct fprobe *fp, unsigned long ip, struct pt_regs *regs) +static void sample_entry_handler(struct fprobe *fp, unsigned long ip, + struct pt_regs *regs, void *data) { if (use_trace) /* @@ -63,7 +64,8 @@ static void sample_entry_handler(struct fprobe *fp, unsigned long ip, struct pt_ show_backtrace(); }
-static void sample_exit_handler(struct fprobe *fp, unsigned long ip, struct pt_regs *regs) +static void sample_exit_handler(struct fprobe *fp, unsigned long ip, struct pt_regs *regs, + void *data) { unsigned long rip = instruction_pointer(regs);