On Wed, Dec 19, 2018 at 10:04 AM Manfred Spraul
<manfred@xxxxxxxxxxxxxxxx> wrote:
Hello Dmitry,
On 12/12/18 11:55 AM, Dmitry Vyukov wrote:
On Tue, Dec 11, 2018 at 9:23 PM syzbotI found one unexpected (incorrect?) locking, see the attached patch.
<syzbot+1145ec2e23165570c3ac@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
Hello,+Manfred, this looks similar to the other few crashes related to
syzbot found the following crash on:
HEAD commit: f5d582777bcb Merge branch 'for-linus' of git://git.kernel...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=135bc547400000
kernel config: https://syzkaller.appspot.com/x/.config?x=c8970c89a0efbb23
dashboard link: https://syzkaller.appspot.com/bug?extid=1145ec2e23165570c3ac
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16803afb400000
semget$private(0x0, 0x4000, 0x3f) that you looked at.
But I doubt that this is the root cause of the crashes.
But why? These one-off sporadic crashes reported by syzbot looks
exactly like a subtle race and your patch touches sem_exit_ns involved
in all reports.
So if you don't spot anything else, I would say close these 3 reports
with this patch (I see you already included Reported-by tags which is
great!) and then wait for syzbot reaction. Since we got 3 of them, if
it's still not fixed I would expect that syzbot will be able to
retrigger this later again.
semget$private(..., 0x4003, ...)
semget$private(..., 0x4006, ...)
semget$private(..., 0x4007, ...)
[ 1201.210245] kmalloc-4194304 4698112KB 4698112KBi.e.: 1147 4 MB kmalloc blocks --> are we leaking nearly 100% of the semaphore arrays??