From 8c427cc2fa73684ea140999e121b7b6c1c717632 Mon Sep 17 00:00:00 2001 From: "Masami Hiramatsu (Google)" Date: Wed, 24 Jan 2024 00:02:34 +0900 Subject: [PATCH 1/3] tracing/probes: Fix to show a parse error for bad type for $comm Fix to show a parse error for bad type (non-string) for $comm/$COMM and immediate-string. With this fix, error_log file shows appropriate error message as below. /sys/kernel/tracing # echo 'p vfs_read $comm:u32' >> kprobe_events sh: write error: Invalid argument /sys/kernel/tracing # echo 'p vfs_read \"hoge":u32' >> kprobe_events sh: write error: Invalid argument /sys/kernel/tracing # cat error_log [ 30.144183] trace_kprobe: error: $comm and immediate-string only accepts string type Command: p vfs_read $comm:u32 ^ [ 62.618500] trace_kprobe: error: $comm and immediate-string only accepts string type Command: p vfs_read \"hoge":u32 ^ Link: https://lore.kernel.org/all/170602215411.215583.2238016352271091852.stgit@devnote2/ Fixes: 3dd1f7f24f8c ("tracing: probeevent: Fix to make the type of $comm string") Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) --- kernel/trace/trace_probe.c | 7 +++++-- kernel/trace/trace_probe.h | 3 ++- 2 files changed, 7 insertions(+), 3 deletions(-) diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index 4dc74d73fc1df..c6da5923e5b9f 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -1159,9 +1159,12 @@ static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size, if (!(ctx->flags & TPARG_FL_TEVENT) && (strcmp(arg, "$comm") == 0 || strcmp(arg, "$COMM") == 0 || strncmp(arg, "\\\"", 2) == 0)) { - /* The type of $comm must be "string", and not an array. */ - if (parg->count || (t && strcmp(t, "string"))) + /* The type of $comm must be "string", and not an array type. */ + if (parg->count || (t && strcmp(t, "string"))) { + trace_probe_log_err(ctx->offset + (t ? (t - arg) : 0), + NEED_STRING_TYPE); goto out; + } parg->type = find_fetch_type("string", ctx->flags); } else parg->type = find_fetch_type(t, ctx->flags); diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h index 850d9ecb6765a..c1877d0182691 100644 --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -515,7 +515,8 @@ extern int traceprobe_define_arg_fields(struct trace_event_call *event_call, C(BAD_HYPHEN, "Failed to parse single hyphen. Forgot '>'?"), \ C(NO_BTF_FIELD, "This field is not found."), \ C(BAD_BTF_TID, "Failed to get BTF type info."),\ - C(BAD_TYPE4STR, "This type does not fit for string."), + C(BAD_TYPE4STR, "This type does not fit for string."),\ + C(NEED_STRING_TYPE, "$comm and immediate-string only accepts string type"), #undef C #define C(a, b) TP_ERR_##a From 9a571c1e275cedacd48c66a6bddd0c23f1dffdbf Mon Sep 17 00:00:00 2001 From: "Masami Hiramatsu (Google)" Date: Wed, 24 Jan 2024 00:03:02 +0900 Subject: [PATCH 2/3] tracing/probes: Fix to set arg size and fmt after setting type from BTF Since the BTF type setting updates probe_arg::type, the type size calculation and setting print-fmt should be done after that. Without this fix, the argument size and print-fmt can be wrong. Link: https://lore.kernel.org/all/170602218196.215583.6417859469540955777.stgit@devnote2/ Fixes: b576e09701c7 ("tracing/probes: Support function parameters if BTF is available") Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) --- kernel/trace/trace_probe.c | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-) diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index c6da5923e5b9f..34289f9c67076 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -1172,18 +1172,6 @@ static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size, trace_probe_log_err(ctx->offset + (t ? (t - arg) : 0), BAD_TYPE); goto out; } - parg->offset = *size; - *size += parg->type->size * (parg->count ?: 1); - - ret = -ENOMEM; - if (parg->count) { - len = strlen(parg->type->fmttype) + 6; - parg->fmt = kmalloc(len, GFP_KERNEL); - if (!parg->fmt) - goto out; - snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype, - parg->count); - } code = tmp = kcalloc(FETCH_INSN_MAX, sizeof(*code), GFP_KERNEL); if (!code) @@ -1207,6 +1195,19 @@ static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size, goto fail; } } + parg->offset = *size; + *size += parg->type->size * (parg->count ?: 1); + + if (parg->count) { + len = strlen(parg->type->fmttype) + 6; + parg->fmt = kmalloc(len, GFP_KERNEL); + if (!parg->fmt) { + ret = -ENOMEM; + goto out; + } + snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype, + parg->count); + } ret = -EINVAL; /* Store operation */ From 9efd24ec5599ed485b7c4d9aeb731141f6285167 Mon Sep 17 00:00:00 2001 From: Li zeming Date: Tue, 19 Sep 2023 09:28:23 +0800 Subject: [PATCH 3/3] kprobes: Remove unnecessary initial values of variables ri and sym is assigned first, so it does not need to initialize the assignment. Link: https://lore.kernel.org/all/20230919012823.7815-1-zeming@nfschina.com/ Signed-off-by: Li zeming Acked-by: Masami Hiramatsu (Google) Signed-off-by: Masami Hiramatsu (Google) --- kernel/kprobes.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/kprobes.c b/kernel/kprobes.c index d5a0ee40bf66c..9d9095e817928 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1993,7 +1993,7 @@ NOKPROBE_SYMBOL(__kretprobe_find_ret_addr); unsigned long kretprobe_find_ret_addr(struct task_struct *tsk, void *fp, struct llist_node **cur) { - struct kretprobe_instance *ri = NULL; + struct kretprobe_instance *ri; kprobe_opcode_t *ret; if (WARN_ON_ONCE(!cur)) @@ -2802,7 +2802,7 @@ static int show_kprobe_addr(struct seq_file *pi, void *v) { struct hlist_head *head; struct kprobe *p, *kp; - const char *sym = NULL; + const char *sym; unsigned int i = *(loff_t *) v; unsigned long offset = 0; char *modname, namebuf[KSYM_NAME_LEN];