Date: Mon, 6 Jan 2003 16:41:39 +0100
To: linux-kernel@vger.kernel.org
Subject: 2.4.20aa1 ide-scsi crashes
Message-ID: <20030106154138.GA2588@ghanima.endorphin.org>
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From: Fruhwirth Clemens <clemens@endorphin.org>
Sender: linux-kernel-owner@vger.kernel.org
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under heavy I/O load for my scsi-emulated cdrom 2.4.20aa1 crashes at

drivers/scsi/scsi_dma:155 with 
panic("scsi_free:Trying to free unused memory")

panic(..) somehow refuses to print the call trace because "IEEE in interrupt
handler - no sync".

The only scsi module I'm using is ide-scsi. As I browsed the aa patch I
recognized that a few &io_request_lock have been exchanged for
"q->queue_lock". But ide-scsi is still locking on io_request_lock. This is
probably the source of the race condition. However I'm not sure because I
think q->queue_lock is being initialized to &io_request_lock, so it should
still be the same lock.

See drivers/scsi/ide-scsi:295 or 
    drivers/scsi/ide-scsi:850 (Why isn't there a lock in that case?)

(done) referrs to sr.c:rw_intr which calls scsi_io_completion which calls
the panic(..)-ing scsi_free)

Any guesses?

Regards, Clemens
Please CC answers, /me not on list.
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