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[PULL,v3,5/8] fuzz: use ITIMER_REAL for timeouts

Message ID 20210901115004.34768-6-alxndr@bu.edu
State New
Headers show
Series [PULL,v3,1/8] fuzz: fix sparse memory access in the DMA callback | expand

Commit Message

Alexander Bulekov Sept. 1, 2021, 11:50 a.m. UTC
Using ITIMER_VIRTUAL is a bad idea, if the fuzzer hits a blocking
syscall - e.g. ppoll with a NULL timespec. This causes timeout issues
while fuzzing some block-device code. Fix that by using wall-clock time.
This might cause inputs to timeout sometimes due to scheduling
effects/ambient load, but it is better than bringing the entire fuzzing
process to a halt.

Based-on: <20210713150037.9297-1-alxndr@bu.edu>
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
---
 tests/qtest/fuzz/generic_fuzz.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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Patch

diff --git a/tests/qtest/fuzz/generic_fuzz.c b/tests/qtest/fuzz/generic_fuzz.c
index 3e8ce29227..de427a3727 100644
--- a/tests/qtest/fuzz/generic_fuzz.c
+++ b/tests/qtest/fuzz/generic_fuzz.c
@@ -695,7 +695,7 @@  static void generic_fuzz(QTestState *s, const unsigned char *Data, size_t Size)
         while (cmd && Size) {
             /* Reset the timeout, each time we run a new command */
             if (timeout) {
-                setitimer(ITIMER_VIRTUAL, &timer, NULL);
+                setitimer(ITIMER_REAL, &timer, NULL);
             }
 
             /* Get the length until the next command or end of input */