From: Masami Hiramatsu mhiramat@kernel.org
commit 2ae5d0d7d8868df7c05c2013c0b9cddd4d40610e upstream.
Since commit 03db8b583d1c ("perf tools: Fix maps__find_symbol_by_name()") introduced map address range check in maps__find_symbol_by_name(), we can not get "_etext" from kernel map because _etext is placed on the edge of the kernel .text section (= kernel map in perf.)
To fix this issue, this checks the address correctness by map address range information (map->start and map->end) instead of using _etext address.
This can cause an error if the target inlined function is embedded in both __init function and normal function.
For exaample, request_resource() is a normal function but also embedded in __init reserve_setup(). In this case, the probe point in reserve_setup() must be skipped.
However, without this fix, it failes to setup all probe points:
# ./perf probe -v request_resource probe-definition(0): request_resource symbol:request_resource file:(null) line:0 offset:0 return:0 lazy:(null) 0 arguments Looking at the vmlinux_path (8 entries long) Using /usr/lib/debug/lib/modules/5.5.17-200.fc31.x86_64/vmlinux for symbols Open Debuginfo file: /usr/lib/debug/lib/modules/5.5.17-200.fc31.x86_64/vmlinux Try to find probe point from debuginfo. Matched function: request_resource [15e29ad] found inline addr: 0xffffffff82fbf892 Probe point found: reserve_setup+204 found inline addr: 0xffffffff810e9790 Probe point found: request_resource+0 Found 2 probe_trace_events. Opening /sys/kernel/debug/tracing//kprobe_events write=1 Opening /sys/kernel/debug/tracing//README write=0 Writing event: p:probe/request_resource _text+33290386 Failed to write event: Invalid argument Error: Failed to add events. Reason: Invalid argument (Code: -22) #
With this fix,
# ./perf probe request_resource reserve_setup is out of .text, skip it. Added new events: (null):(null) (on request_resource) probe:request_resource (on request_resource)
You can now use it in all perf tools, such as:
perf record -e probe:request_resource -aR sleep 1
#
Fixes: 03db8b583d1c ("perf tools: Fix maps__find_symbol_by_name()") Reported-by: Arnaldo Carvalho de Melo acme@kernel.org Signed-off-by: Masami Hiramatsu mhiramat@kernel.org Tested-by: Arnaldo Carvalho de Melo acme@redhat.com Cc: Jiri Olsa jolsa@kernel.org Cc: Namhyung Kim namhyung@kernel.org Cc: stable@vger.kernel.org Link: http://lore.kernel.org/lkml/158763967332.30755.4922496724365529088.stgit@dev... Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- tools/perf/util/probe-event.c | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-)
--- a/tools/perf/util/probe-event.c +++ b/tools/perf/util/probe-event.c @@ -245,21 +245,22 @@ static void clear_probe_trace_events(str static bool kprobe_blacklist__listed(unsigned long address); static bool kprobe_warn_out_range(const char *symbol, unsigned long address) { - u64 etext_addr = 0; - int ret; + struct map *map; + bool ret = false;
- /* Get the address of _etext for checking non-probable text symbol */ - ret = kernel_get_symbol_address_by_name("_etext", &etext_addr, - false, false); - - if (ret == 0 && etext_addr < address) - pr_warning("%s is out of .text, skip it.\n", symbol); - else if (kprobe_blacklist__listed(address)) + map = kernel_get_module_map(NULL); + if (map) { + ret = address <= map->start || map->end < address; + if (ret) + pr_warning("%s is out of .text, skip it.\n", symbol); + map__put(map); + } + if (!ret && kprobe_blacklist__listed(address)) { pr_warning("%s is blacklisted function, skip it.\n", symbol); - else - return false; + ret = true; + }
- return true; + return ret; }
/*