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author | Marcin Slusarz <marcin.slusarz@gmail.com> | 2010-07-28 01:18:01 +0200 |
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committer | Steven Rostedt <rostedt@goodmis.org> | 2010-08-13 15:23:16 -0400 |
commit | 1aa54bca6ee0d07ebcafb8ca8074b624d80724aa (patch) | |
tree | 815f3c1d184b61958ee48eb868ed28b1e5aab278 /scripts/unifdef.c | |
parent | 2a37a3df57c44e947271758a1aa4bea7bff9feab (diff) | |
download | linux-stable-1aa54bca6ee0d07ebcafb8ca8074b624d80724aa.tar.gz linux-stable-1aa54bca6ee0d07ebcafb8ca8074b624d80724aa.tar.bz2 linux-stable-1aa54bca6ee0d07ebcafb8ca8074b624d80724aa.zip |
tracing: Sanitize value returned from write(trace_marker, "...", len)
When userspace code writes non-new-line-terminated string to trace_marker
file, write handler appends new-line and returns number of bytes written
to trace buffer, so
write(fd, "abc", 3) will return 4
That's unexpected and unfortunately it confuses glibc's fprintf function.
Example:
int main() {
fprintf(stderr, "abc");
return 0;
}
$ gcc test.c -o test
$ echo mmiotrace > /sys/kernel/debug/tracing/current_tracer
$ ./test 2>/sys/kernel/debug/tracing/trace_marker
results in infinite loop:
write(fd, "abc", 3) = 4
write(fd, "", 1) = 0
write(fd, "", 1) = 0
write(fd, "", 1) = 0
write(fd, "", 1) = 0
write(fd, "", 1) = 0
write(fd, "", 1) = 0
write(fd, "", 1) = 0
(...)
...and kernel trace buffer full of empty markers.
Fix it by sanitizing write return value.
Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
LKML-Reference: <20100727231801.GB2826@joi.lan>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'scripts/unifdef.c')
0 files changed, 0 insertions, 0 deletions