Messages in this thread Patch in this message | | | From | "Masami Hiramatsu (Google)" <> | Subject | [PATCH 3/3] tracing/probes: Fix return value when "(fault)" is injected | Date | Sun, 2 Jul 2023 23:47:35 +0900 |
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From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
When the "(fault)" is injected, the return value of fetch_store_string*() should be the length of the "(fault)", but an error code is returned. Fix it to return the correct length and update the data_loc according the updated length. This needs to update a ftracetest test case, which expects trace output to appear as '(fault)' instead of '"(fault)"'.
Fixes: 2e9906f84fc7 ("tracing: Add "(fault)" name injection to kernel probes") Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> --- kernel/trace/trace_probe_kernel.h | 17 +++++++---------- .../ftrace/test.d/kprobe/kprobe_args_user.tc | 2 +- 2 files changed, 8 insertions(+), 11 deletions(-)
diff --git a/kernel/trace/trace_probe_kernel.h b/kernel/trace/trace_probe_kernel.h index c4e1d4c03a85..63d90fe4eb87 100644 --- a/kernel/trace/trace_probe_kernel.h +++ b/kernel/trace/trace_probe_kernel.h @@ -48,14 +48,15 @@ fetch_store_strlen(unsigned long addr) return (ret < 0) ? strlen(FAULT_STRING) + 1 : len; } -static nokprobe_inline void set_data_loc(int ret, void *dest, void *__dest, void *base, int len) +static nokprobe_inline int set_data_loc(int ret, void *dest, void *__dest, void *base, int len) { - if (ret >= 0) { - *(u32 *)dest = make_data_loc(ret, __dest - base); - } else { + if (ret < 0) { strscpy(__dest, FAULT_STRING, len); ret = strlen(__dest) + 1; } + + *(u32 *)dest = make_data_loc(ret, __dest - base); + return ret; } /* @@ -76,9 +77,7 @@ fetch_store_string_user(unsigned long addr, void *dest, void *base) __dest = get_loc_data(dest, base); ret = strncpy_from_user_nofault(__dest, uaddr, maxlen); - set_data_loc(ret, dest, __dest, base, maxlen); - - return ret; + return set_data_loc(ret, dest, __dest, base, maxlen); } /* @@ -107,9 +106,7 @@ fetch_store_string(unsigned long addr, void *dest, void *base) * probing. */ ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen); - set_data_loc(ret, dest, __dest, base, maxlen); - - return ret; + return set_data_loc(ret, dest, __dest, base, maxlen); } static nokprobe_inline int diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_user.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_user.tc index d25d01a19778..8dcc0b29bd36 100644 --- a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_user.tc +++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_user.tc @@ -29,6 +29,6 @@ echo 1 > events/kprobes/myevent/enable ln -s foo $TMPDIR/bar echo 0 > events/kprobes/myevent/enable -grep myevent trace | grep -q 'path=(fault) path2=(fault)' +grep myevent trace | grep -q 'path="*(fault)"* path2="*(fault)"*' exit 0
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