From 561ca66910bf597f170be5a7aa531c4e05f8e9be Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Mon, 2 Nov 2020 11:28:39 -0500 Subject: [PATCH] tracing: Make -ENOMEM the default error for parse_synth_field() parse_synth_field() returns a pointer and requires that errors get surrounded by ERR_PTR(). The ret variable is initialized to zero, but should never be used as zero, and if it is, it could cause a false return code and produce a NULL pointer dereference. It makes no sense to set ret to zero. Set ret to -ENOMEM (the most common error case), and have any other errors set it to something else. This removes the need to initialize ret on *every* error branch. Fixes: 761a8c58db6b ("tracing, synthetic events: Replace buggy strcat() with seq_buf operations") Reported-by: Dan Carpenter Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_events_synth.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-) diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c index 84b7cab55291..881df991742a 100644 --- a/kernel/trace/trace_events_synth.c +++ b/kernel/trace/trace_events_synth.c @@ -584,7 +584,7 @@ static struct synth_field *parse_synth_field(int argc, const char **argv, { struct synth_field *field; const char *prefix = NULL, *field_type = argv[0], *field_name, *array; - int len, ret = 0; + int len, ret = -ENOMEM; struct seq_buf s; ssize_t size; @@ -617,10 +617,9 @@ static struct synth_field *parse_synth_field(int argc, const char **argv, len--; field->name = kmemdup_nul(field_name, len, GFP_KERNEL); - if (!field->name) { - ret = -ENOMEM; + if (!field->name) goto free; - } + if (!is_good_name(field->name)) { synth_err(SYNTH_ERR_BAD_NAME, errpos(field_name)); ret = -EINVAL; @@ -638,10 +637,9 @@ static struct synth_field *parse_synth_field(int argc, const char **argv, len += strlen(prefix); field->type = kzalloc(len, GFP_KERNEL); - if (!field->type) { - ret = -ENOMEM; + if (!field->type) goto free; - } + seq_buf_init(&s, field->type, len); if (prefix) seq_buf_puts(&s, prefix); @@ -653,6 +651,7 @@ static struct synth_field *parse_synth_field(int argc, const char **argv, } if (WARN_ON_ONCE(!seq_buf_buffer_left(&s))) goto free; + s.buffer[s.len] = '\0'; size = synth_field_size(field->type); @@ -666,10 +665,8 @@ static struct synth_field *parse_synth_field(int argc, const char **argv, len = sizeof("__data_loc ") + strlen(field->type) + 1; type = kzalloc(len, GFP_KERNEL); - if (!type) { - ret = -ENOMEM; + if (!type) goto free; - } seq_buf_init(&s, type, len); seq_buf_puts(&s, "__data_loc ");