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author | Masami Hiramatsu <mhiramat@kernel.org> | 2019-10-29 09:31:44 +0100 |
---|---|---|
committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2019-11-14 19:15:12 +0100 |
commit | c7411a1a126f649be71526a36d4afac9e5aefa13 (patch) | |
tree | 4e9c314806469e2fb762189b535fd6410cba134b /kernel/trace/trace_kprobe.c | |
parent | tracing: use kvcalloc for tgid_map array allocation (diff) | |
download | linux-c7411a1a126f649be71526a36d4afac9e5aefa13.tar.xz linux-c7411a1a126f649be71526a36d4afac9e5aefa13.zip |
tracing/kprobe: Check whether the non-suffixed symbol is notrace
Check whether the non-suffixed symbol is notrace, since suffixed
symbols are generated by the compilers for optimization. Based on
these suffixed symbols, notrace check might not work because
some of them are just a partial code of the original function.
(e.g. cold-cache (unlikely) code is separated from original
function as FUNCTION.cold.XX)
For example, without this fix,
# echo p device_add.cold.67 > /sys/kernel/debug/tracing/kprobe_events
sh: write error: Invalid argument
# cat /sys/kernel/debug/tracing/error_log
[ 135.491035] trace_kprobe: error: Failed to register probe event
Command: p device_add.cold.67
^
# dmesg | tail -n 1
[ 135.488599] trace_kprobe: Could not probe notrace function device_add.cold.67
With this,
# echo p device_add.cold.66 > /sys/kernel/debug/tracing/kprobe_events
# cat /sys/kernel/debug/kprobes/list
ffffffff81599de9 k device_add.cold.66+0x0 [DISABLED]
Actually, kprobe blacklist already did similar thing,
see within_kprobe_blacklist().
Link: http://lkml.kernel.org/r/157233790394.6706.18243942030937189679.stgit@devnote2
Fixes: 45408c4f9250 ("tracing: kprobes: Prohibit probing on notrace function")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace_kprobe.c')
-rw-r--r-- | kernel/trace/trace_kprobe.c | 27 |
1 files changed, 24 insertions, 3 deletions
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 1552a95c743b..7f890262c8a3 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -435,11 +435,10 @@ static int disable_trace_kprobe(struct trace_event_call *call, #if defined(CONFIG_KPROBES_ON_FTRACE) && \ !defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE) -static bool within_notrace_func(struct trace_kprobe *tk) +static bool __within_notrace_func(unsigned long addr) { - unsigned long offset, size, addr; + unsigned long offset, size; - addr = trace_kprobe_address(tk); if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset)) return false; @@ -452,6 +451,28 @@ static bool within_notrace_func(struct trace_kprobe *tk) */ return !ftrace_location_range(addr, addr + size - 1); } + +static bool within_notrace_func(struct trace_kprobe *tk) +{ + unsigned long addr = addr = trace_kprobe_address(tk); + char symname[KSYM_NAME_LEN], *p; + + if (!__within_notrace_func(addr)) + return false; + + /* Check if the address is on a suffixed-symbol */ + if (!lookup_symbol_name(addr, symname)) { + p = strchr(symname, '.'); + if (!p) + return true; + *p = '\0'; + addr = (unsigned long)kprobe_lookup_name(symname, 0); + if (addr) + return __within_notrace_func(addr); + } + + return true; +} #else #define within_notrace_func(tk) (false) #endif |