From: Jeremy Linton <jeremy.linton@arm.com>
To: linux-kernel@vger.kernel.org
Cc: peterz@infradead.org, mingo@redhat.com,
Jeremy Linton <jeremy.linton@arm.com>
Subject: [PATCH] locktorture: Fix Oops when reader/writer count is 0
Date: Tue, 10 Oct 2017 10:52:48 -0500 [thread overview]
Message-ID: <20171010155248.11602-1-jeremy.linton@arm.com> (raw)
If nwriters_stress=0 is passed to the lock torture test
it will panic in:
Internal error: Oops: 96000005 [#1] SMP
...
[<ffff000000b7022c>] __torture_print_stats+0x2c/0x1c8 [locktorture]
[<ffff000000b7070c>] lock_torture_stats_print+0x74/0x120 [locktorture]
[<ffff000000b707f8>] lock_torture_stats+0x40/0xa8 [locktorture]
[<ffff0000080f3570>] kthread+0x108/0x138
[<ffff000008084b90>] ret_from_fork+0x10/0x18
This is caused by the deference to a null statp. Fix that by
checking the n_stress for non zero count before referencing statp.
Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
---
kernel/locking/locktorture.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index f24582d4dad3..8229ba7147e5 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -716,10 +716,14 @@ static void __torture_print_stats(char *page,
bool fail = 0;
int i, n_stress;
long max = 0;
- long min = statp[0].n_lock_acquired;
+ long min = 0;
long long sum = 0;
n_stress = write ? cxt.nrealwriters_stress : cxt.nrealreaders_stress;
+
+ if (n_stress)
+ min = statp[0].n_lock_acquired;
+
for (i = 0; i < n_stress; i++) {
if (statp[i].n_lock_fail)
fail = true;
--
2.13.5
next reply other threads:[~2017-10-10 15:53 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-10 15:52 Jeremy Linton [this message]
2017-11-07 20:01 ` [PATCH] locktorture: Fix Oops when reader/writer count is 0 Jeremy Linton
2017-11-07 21:07 ` Peter Zijlstra
2017-11-07 22:15 ` Paul E. McKenney
2017-11-08 8:27 ` Peter Zijlstra
2017-11-08 14:17 ` Paul E. McKenney
2017-11-08 14:45 ` Davidlohr Bueso
2017-11-08 16:48 ` Paul E. McKenney
2017-11-08 16:57 ` Jeremy Linton
2017-11-08 17:44 ` Paul E. McKenney
2017-11-09 16:15 ` Jeremy Linton
2017-11-09 16:19 ` Davidlohr Bueso
2017-11-09 16:45 ` Paul E. McKenney
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