| Message ID | 168908496683.123124.4761206188794205601.stgit@devnote2 (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 797311bce5c2ac90b8d65e357603cfd410d36ebb |
| Delegated to: | Masami Hiramatsu |
| Headers | show |
| Series | tracing/probes: Fix bugs in process_fetch_insn | expand |
On Tue, 11 Jul 2023 23:16:07 +0900 "Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote: > From: Masami Hiramatsu (Google) <mhiramat@kernel.org> > > Fix to record 0-length data to data_loc in fetch_store_string*() if it fails > to get the string data. > Currently those expect that the data_loc is updated by store_trace_args() if > it returns the error code. However, that does not work correctly if the > argument is an array of strings. In that case, store_trace_args() only clears > the first entry of the array (which may have no error) and leaves other > entries. So it should be cleared by fetch_store_string*() itself. > Also, 'dyndata' and 'maxlen' in store_trace_args() should be updated > only if it is used (ret > 0 and argument is a dynamic data.) > > Fixes: 40b53b771806 ("tracing: probeevent: Add array type support") > Cc: stable@vger.kernel.org > Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> > --- > Changes in v4: > - Simplify the updating data_loc code with set_data_loc(). > Changes in v5: > - Move out arg->dynamic check from unlikely() and use likely(). > --- > kernel/trace/trace_probe_kernel.h | 13 +++++++++---- > kernel/trace/trace_probe_tmpl.h | 10 +++------- > kernel/trace/trace_uprobe.c | 3 ++- > 3 files changed, 14 insertions(+), 12 deletions(-) > Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> -- Steve
diff --git a/kernel/trace/trace_probe_kernel.h b/kernel/trace/trace_probe_kernel.h index 6deae2ce34f8..bb723eefd7b7 100644 --- a/kernel/trace/trace_probe_kernel.h +++ b/kernel/trace/trace_probe_kernel.h @@ -37,6 +37,13 @@ fetch_store_strlen(unsigned long addr) return (ret < 0) ? ret : len; } +static nokprobe_inline void set_data_loc(int ret, void *dest, void *__dest, void *base) +{ + if (ret < 0) + ret = 0; + *(u32 *)dest = make_data_loc(ret, __dest - base); +} + /* * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf * with max length and relative data location. @@ -55,8 +62,7 @@ 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); - if (ret >= 0) - *(u32 *)dest = make_data_loc(ret, __dest - base); + set_data_loc(ret, dest, __dest, base); return ret; } @@ -87,8 +93,7 @@ fetch_store_string(unsigned long addr, void *dest, void *base) * probing. */ ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen); - if (ret >= 0) - *(u32 *)dest = make_data_loc(ret, __dest - base); + set_data_loc(ret, dest, __dest, base); return ret; } diff --git a/kernel/trace/trace_probe_tmpl.h b/kernel/trace/trace_probe_tmpl.h index 185da001f4c3..3935b347f874 100644 --- a/kernel/trace/trace_probe_tmpl.h +++ b/kernel/trace/trace_probe_tmpl.h @@ -267,13 +267,9 @@ store_trace_args(void *data, struct trace_probe *tp, void *rec, if (unlikely(arg->dynamic)) *dl = make_data_loc(maxlen, dyndata - base); ret = process_fetch_insn(arg->code, rec, dl, base); - if (arg->dynamic) { - if (unlikely(ret < 0)) { - *dl = make_data_loc(0, dyndata - base); - } else { - dyndata += ret; - maxlen -= ret; - } + if (arg->dynamic && likely(ret > 0)) { + dyndata += ret; + maxlen -= ret; } } } diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index 8b92e34ff0c8..7b47e9a2c010 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -170,7 +170,8 @@ fetch_store_string(unsigned long addr, void *dest, void *base) */ ret++; *(u32 *)dest = make_data_loc(ret, (void *)dst - base); - } + } else + *(u32 *)dest = make_data_loc(0, (void *)dst - base); return ret; }