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authorMasami Hiramatsu2019-05-15 07:38:30 +0200
committerSteven Rostedt (VMware)2019-05-26 05:04:42 +0200
commit88903c464321cdbc2d473c24cbf311f576cf05bc (patch)
tree79d0b37b1ac3b805d67651687f9ca866e5df059a /kernel/trace/trace_probe.c
parentuaccess: Add non-pagefault user-space read functions (diff)
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tracing/probe: Add ustring type for user-space string
Add "ustring" type for fetching user-space string from kprobe event. User can specify ustring type at uprobe event, and it is same as "string" for uprobe. Note that probe-event provides this option but it doesn't choose the correct type automatically since we have not way to decide the address is in user-space or not on some arch (and on some other arch, you can fetch the string by "string" type). So user must carefully check the target code (e.g. if you see __user on the target variable) and use this new type. Link: http://lkml.kernel.org/r/155789871009.26965.14167558859557329331.stgit@devnote2 Acked-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace_probe.c')
-rw-r--r--kernel/trace/trace_probe.c14
1 files changed, 11 insertions, 3 deletions
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index a347faced959..5a0470f7b9de 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -78,6 +78,8 @@ static const struct fetch_type probe_fetch_types[] = {
/* Special types */
__ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1,
"__data_loc char[]"),
+ __ASSIGN_FETCH_TYPE("ustring", string, string, sizeof(u32), 1,
+ "__data_loc char[]"),
/* Basic types */
ASSIGN_FETCH_TYPE(u8, u8, 0),
ASSIGN_FETCH_TYPE(u16, u16, 0),
@@ -569,7 +571,8 @@ static int traceprobe_parse_probe_arg_body(char *arg, ssize_t *size,
goto fail;
/* Store operation */
- if (!strcmp(parg->type->name, "string")) {
+ if (!strcmp(parg->type->name, "string") ||
+ !strcmp(parg->type->name, "ustring")) {
if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_IMM &&
code->op != FETCH_OP_COMM) {
trace_probe_log_err(offset + (t ? (t - arg) : 0),
@@ -590,7 +593,11 @@ static int traceprobe_parse_probe_arg_body(char *arg, ssize_t *size,
goto fail;
}
}
- code->op = FETCH_OP_ST_STRING; /* In DEREF case, replace it */
+ /* If op == DEREF, replace it with STRING */
+ if (!strcmp(parg->type->name, "ustring"))
+ code->op = FETCH_OP_ST_USTRING;
+ else
+ code->op = FETCH_OP_ST_STRING;
code->size = parg->type->size;
parg->dynamic = true;
} else if (code->op == FETCH_OP_DEREF) {
@@ -618,7 +625,8 @@ static int traceprobe_parse_probe_arg_body(char *arg, ssize_t *size,
/* Loop(Array) operation */
if (parg->count) {
if (scode->op != FETCH_OP_ST_MEM &&
- scode->op != FETCH_OP_ST_STRING) {
+ scode->op != FETCH_OP_ST_STRING &&
+ scode->op != FETCH_OP_ST_USTRING) {
trace_probe_log_err(offset + (t ? (t - arg) : 0),
BAD_STRING);
ret = -EINVAL;