On Fri, 19 Jan 2024 09:38:46 +0800 Ye Bin <[email protected]> wrote:
> Similar to '%pd' for printk, use 'pd' for print struct dentry's name. No, please use '%pd' as a type instead. > > Signed-off-by: Ye Bin <[email protected]> > --- > kernel/trace/trace_probe.c | 38 ++++++++++++++++++++++++++++++++++++++ > 1 file changed, 38 insertions(+) > > diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c > index 4dc74d73fc1d..460f98b85b1c 100644 > --- a/kernel/trace/trace_probe.c > +++ b/kernel/trace/trace_probe.c > @@ -11,6 +11,7 @@ > */ > #define pr_fmt(fmt) "trace_probe: " fmt > > +#include <linux/dcache.h> > #include <linux/bpf.h> > #include "trace_btf.h" > > @@ -86,6 +87,8 @@ static const struct fetch_type probe_fetch_types[] = { > "__data_loc char[]"), > __ASSIGN_FETCH_TYPE("symstr", string, string, sizeof(u32), 1, 1, > "__data_loc char[]"), > + __ASSIGN_FETCH_TYPE("pd", string, string, sizeof(u32), 1, 1, > + "__data_loc char[]"), And you don't need to add a new type. Similar to the preprocessor macro, this should be done before parsing the args. See traceprobe_expand_meta_args(), you can scan the args and search argument end with ':%pd'. If you find that, you can replace it with "+0x%lx(%s):string". Then, you don't need any of these complex fetch type. Thank you, > /* Basic types */ > ASSIGN_FETCH_TYPE(u8, u8, 0), > ASSIGN_FETCH_TYPE(u16, u16, 0), > @@ -1090,6 +1093,25 @@ static int __parse_bitfield_probe_arg(const char *bf, > return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0; > } > > +static char* traceprobe_expand_dentry(const char *argv) > +{ > + #define DENTRY_EXPAND_LEN 7 /* +0xXX() */ > + char *new_argv; > + int len = strlen(argv) + 1 + DENTRY_EXPAND_LEN; > + > + new_argv = kmalloc(len, GFP_KERNEL); > + if (!new_argv) > + return NULL; > + > + if (snprintf(new_argv, len, "+0x%lx(%s)", > + offsetof(struct dentry, d_name.name), argv) >= len) { > + kfree(new_argv); > + return NULL; > + } > + > + return new_argv; > +} > + > /* String length checking wrapper */ > static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size, > struct probe_arg *parg, > @@ -1099,6 +1121,7 @@ static int traceprobe_parse_probe_arg_body(const char > *argv, ssize_t *size, > char *t, *t2, *t3; > int ret, len; > char *arg; > + char *org_arg = NULL; > > arg = kstrdup(argv, GFP_KERNEL); > if (!arg) > @@ -1182,6 +1205,16 @@ static int traceprobe_parse_probe_arg_body(const char > *argv, ssize_t *size, > parg->count); > } > > + if (!strcmp("pd", parg->type->name)) { > + char *temp; > + > + temp = traceprobe_expand_dentry(arg); > + if (!temp) > + goto out; > + org_arg = arg; > + arg = temp; > + } > + > code = tmp = kcalloc(FETCH_INSN_MAX, sizeof(*code), GFP_KERNEL); > if (!code) > goto out; > @@ -1243,6 +1276,10 @@ static int traceprobe_parse_probe_arg_body(const char > *argv, ssize_t *size, > goto fail; > } > } > + > + if (!strcmp(parg->type->name, "pd")) > + code++; > + > /* If op == DEREF, replace it with STRING */ > if (!strcmp(parg->type->name, "ustring") || > code->op == FETCH_OP_UDEREF) > @@ -1321,6 +1358,7 @@ static int traceprobe_parse_probe_arg_body(const char > *argv, ssize_t *size, > kfree(tmp); > out: > kfree(arg); > + kfree(org_arg); > > return ret; > } > -- > 2.31.1 > -- Masami Hiramatsu (Google) <[email protected]>
