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author | Beau Belgrave <beaub@linux.microsoft.com> | 2023-04-19 14:41:40 -0700 |
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committer | Steven Rostedt (Google) <rostedt@goodmis.org> | 2023-04-25 20:11:26 -0400 |
commit | c7bdb07902e0b633795372665d0154e7267ecd0e (patch) | |
tree | f6e8b632585c7f5ff529be4852afb353130f4f1b /kernel/trace/trace_output.c | |
parent | 9872c07b14e5ad3e3a89a7fd43e9488072007118 (diff) | |
download | linux-stable-c7bdb07902e0b633795372665d0154e7267ecd0e.tar.gz linux-stable-c7bdb07902e0b633795372665d0154e7267ecd0e.tar.bz2 linux-stable-c7bdb07902e0b633795372665d0154e7267ecd0e.zip |
tracing: Fix print_fields() for __dyn_loc/__rel_loc
Both print_fields() and print_array() do not handle if dynamic data ends
at the last byte of the payload for both __dyn_loc and __rel_loc field
types. For __rel_loc, the offset was off by 4 bytes, leading to
incorrect strings and data being printed out. In print_array() the
buffer pos was missed from being advanced, which results in the first
payload byte being used as the offset base instead of the field offset.
Advance __rel_loc offset by 4 to ensure correct offset and advance pos
to the field offset to ensure correct data is displayed when printing
arrays. Change >= to > when checking if data is in-bounds, since it's
valid for dynamic data to include the last byte of the payload.
Example outputs for event format:
field:unsigned short common_type; offset:0; size:2; signed:0;
field:unsigned char common_flags; offset:2; size:1; signed:0;
field:unsigned char common_preempt_count; offset:3; size:1; signed:0;
field:int common_pid; offset:4; size:4; signed:1;
field:__rel_loc char text[]; offset:8; size:4; signed:1;
Output before:
tp_rel_loc: text=<OVERFLOW>
Output after:
tp_rel_loc: text=Test
Link: https://lkml.kernel.org/r/20230419214140.4158-3-beaub@linux.microsoft.com
Fixes: 80a76994b2d8 ("tracing: Add "fields" option to show raw trace event fields")
Reported-by: Doug Cook <dcook@linux.microsoft.com>
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace_output.c')
-rw-r--r-- | kernel/trace/trace_output.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index 780c6971c944..952cc8aa8e59 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -819,13 +819,15 @@ static void print_array(struct trace_iterator *iter, void *pos, len = *(int *)pos >> 16; if (field) - offset += field->offset; + offset += field->offset + sizeof(int); - if (offset + len >= iter->ent_size) { + if (offset + len > iter->ent_size) { trace_seq_puts(&iter->seq, "<OVERFLOW>"); return; } + pos = (void *)iter->ent + offset; + for (i = 0; i < len; i++, pos++) { if (i) trace_seq_putc(&iter->seq, ','); @@ -861,9 +863,9 @@ static void print_fields(struct trace_iterator *iter, struct trace_event_call *c len = *(int *)pos >> 16; if (field->filter_type == FILTER_RDYN_STRING) - offset += field->offset; + offset += field->offset + sizeof(int); - if (offset + len >= iter->ent_size) { + if (offset + len > iter->ent_size) { trace_seq_puts(&iter->seq, "<OVERFLOW>"); break; } |