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author | Miguel Ojeda <miguel.ojeda.sandonis@gmail.com> | 2019-05-23 14:45:35 +0200 |
---|---|---|
committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2019-05-25 23:04:30 -0400 |
commit | 0c97bf863efce63d6ab7971dad811601e6171d2f (patch) | |
tree | f89121ef5eea42f3edb1febfb28181721f153efc /kernel/trace/trace.c | |
parent | 4eebe38a37f9397ffecd4bd3afbdf36838a97969 (diff) |
tracing: Silence GCC 9 array bounds warning
Starting with GCC 9, -Warray-bounds detects cases when memset is called
starting on a member of a struct but the size to be cleared ends up
writing over further members.
Such a call happens in the trace code to clear, at once, all members
after and including `seq` on struct trace_iterator:
In function 'memset',
inlined from 'ftrace_dump' at kernel/trace/trace.c:8914:3:
./include/linux/string.h:344:9: warning: '__builtin_memset' offset
[8505, 8560] from the object at 'iter' is out of the bounds of
referenced subobject 'seq' with type 'struct trace_seq' at offset
4368 [-Warray-bounds]
344 | return __builtin_memset(p, c, size);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
In order to avoid GCC complaining about it, we compute the address
ourselves by adding the offsetof distance instead of referring
directly to the member.
Since there are two places doing this clear (trace.c and trace_kdb.c),
take the chance to move the workaround into a single place in
the internal header.
Link: http://lkml.kernel.org/r/20190523124535.GA12931@gmail.com
Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
[ Removed unnecessary parenthesis around "iter" ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace.c')
-rw-r--r-- | kernel/trace/trace.c | 6 |
1 files changed, 1 insertions, 5 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 2c92b3d9ea30..1c80521fd436 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -8910,12 +8910,8 @@ void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) cnt++; - /* reset all but tr, trace, and overruns */ - memset(&iter.seq, 0, - sizeof(struct trace_iterator) - - offsetof(struct trace_iterator, seq)); + trace_iterator_reset(&iter); iter.iter_flags |= TRACE_FILE_LAT_FMT; - iter.pos = -1; if (trace_find_next_entry_inc(&iter) != NULL) { int ret; |