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Date:   Tue, 13 Apr 2021 14:43:35 -0400
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Dmitry Vyukov <dvyukov@google.com>
Cc:     syzkaller <syzkaller@googlegroups.com>,
        syzbot <syzbot+61e04e51b7ac86930589@syzkaller.appspotmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Jens Axboe <axboe@kernel.dk>, Borislav Petkov <bp@alien8.de>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Jim Mattson <jmattson@google.com>,
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        linux-block <linux-block@vger.kernel.org>,
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        Mark Rutland <mark.rutland@arm.com>, masahiroy@kernel.org,
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        Peter Zijlstra <peterz@infradead.org>,
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        Wanpeng Li <wanpengli@tencent.com>,
        Will Deacon <will@kernel.org>,
        "the arch/x86 maintainers" <x86@kernel.org>
Subject: Re: [syzbot] possible deadlock in del_gendisk
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On Tue, 13 Apr 2021 14:40:09 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> ------------[ cut here ]------------
> raw_local_irq_restore() called with IRQs enabled
> WARNING: CPU: 0 PID: 8777 at kernel/locking/irqflag-debug.c:9 warn_bogus_irq_restore kernel/locking/irqflag-debug.c:9 [inline]
> WARNING: CPU: 0 PID: 8777 at kernel/locking/irqflag-debug.c:9 warn_bogus_irq_restore+0x1d/0x20 kernel/locking/irqflag-debug.c:7

In fact, when you have the above, which is a WARN() with text:

 "raw_local_irq_restore() called with IRQs enabled"

It is pretty much guaranteed that all triggers of this bug will have the
above warning with the same text.

-- Steve