diff options
| author | Ye Bin <yebin10@huawei.com> | 2024-03-22 14:43:04 +0800 |
|---|---|---|
| committer | Masami Hiramatsu (Google) <mhiramat@kernel.org> | 2024-05-01 23:18:47 +0900 |
| commit | d9b15224dd8ff83b2aef87e4cd5ad10c875ef7d6 (patch) | |
| tree | c1d1044c46b3169d35e452878866f9332539efaa /kernel/trace/trace_kprobe.c | |
| parent | cdf355cc60e388d992bdd205b8ee70dc4d533461 (diff) | |
tracing/probes: support '%pd' type for print struct dentry's name
During fault locating, the file name needs to be printed based on the
dentry address. The offset needs to be calculated each time, which
is troublesome. Similar to printk, kprobe support print type '%pd' for
print dentry's name. For example "name=$arg1:%pd" casts the `$arg1`
as (struct dentry *), dereferences the "d_name.name" field and stores
it to "name" argument as a kernel string.
Here is an example:
[tracing]# echo 'p:testprobe dput name=$arg1:%pd' > kprobe_events
[tracing]# echo 1 > events/kprobes/testprobe/enable
[tracing]# grep -q "1" events/kprobes/testprobe/enable
[tracing]# echo 0 > events/kprobes/testprobe/enable
[tracing]# cat trace | grep "enable"
bash-14844 [002] ..... 16912.889543: testprobe: (dput+0x4/0x30) name="enable"
grep-15389 [003] ..... 16922.834182: testprobe: (dput+0x4/0x30) name="enable"
grep-15389 [003] ..... 16922.836103: testprobe: (dput+0x4/0x30) name="enable"
bash-14844 [001] ..... 16931.820909: testprobe: (dput+0x4/0x30) name="enable"
Note that this expects the given argument (e.g. $arg1) is an address of struct
dentry. User must ensure it.
Link: https://lore.kernel.org/all/20240322064308.284457-2-yebin10@huawei.com/
Signed-off-by: Ye Bin <yebin10@huawei.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Diffstat (limited to 'kernel/trace/trace_kprobe.c')
| -rw-r--r-- | kernel/trace/trace_kprobe.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 14099cc17fc9..c68d4e830fbe 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -782,6 +782,7 @@ static int __trace_kprobe_create(int argc, const char *argv[]) char buf[MAX_EVENT_NAME_LEN]; char gbuf[MAX_EVENT_NAME_LEN]; char abuf[MAX_BTF_ARGS_LEN]; + char *dbuf = NULL; struct traceprobe_parse_context ctx = { .flags = TPARG_FL_KERNEL }; switch (argv[0][0]) { @@ -933,6 +934,10 @@ static int __trace_kprobe_create(int argc, const char *argv[]) argv = new_argv; } + ret = traceprobe_expand_dentry_args(argc, argv, &dbuf); + if (ret) + goto out; + /* setup a probe */ tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive, argc, is_return); @@ -979,6 +984,7 @@ out: trace_probe_log_clear(); kfree(new_argv); kfree(symbol); + kfree(dbuf); return ret; parse_error: |