NetBSD-Bugs archive

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Old Index]

Re: kern/56925: Amd64 server randomly panics

The following reply was made to PR kern/56925; it has been noted by GNATS.

From: Taylor R Campbell <>
Subject: Re: kern/56925: Amd64 server randomly panics
Date: Thu, 14 Jul 2022 18:26:39 +0000

 So it is in wake_ccb, as I guessed, and it looks like conn is null
 when wake_ccb tries to acquire conn->c_lock:
 This can only happen if free_ccb had run before (or concurrently with)
 ccb_timeout, nulling out ccb->ccb_connection before ccb_timeout read
 Which free_ccb did it is not clear to me (lots of calls to it).  But
 my guess is a race between successful command completion and the
 callout firing.  If successful command completion tries callout_stop
 to stop the timeout, but the callout had already begun firing on
 another CPU, then successful command completion might call free_ccb
 and null out ccb->ccb_connection just before ccb_timeout grabs it.
 mlelstv: You recently(ish) worked on MP iscsi -- can you take a look?

Home | Main Index | Thread Index | Old Index