cvs commit: src/sys/geom geom_disk.c

[M. Warner Losh]

In message: <20030514124835.GE4390 at wantadilla.lemis.com>
            "Greg 'groggy' Lehey" <grog at FreeBSD.org> writes:
: On Wednesday, 14 May 2003 at 13:37:59 +0200, Poul-Henning Kamp wrote:
: > In message <20030514081041.GD4390 at wantadilla.lemis.com>, "Greg 'groggy' Lehey"
: > writes:
: >
: >> malloc() of "16" with the following non-sleepablelocks held:
: >> exclusive sleep mutex g_xup r = 0 (0xc8612ca8) locked @ /src/FreeBSD/5-CURRENT-ZAPHOD/src/sys/geom/geom_io.c:363
: >
: > This is a problem, you cannot sleep in the primary I/O path (ie: strategy()
: > and done()), if you sleep in the I/O path, you stop all I/O processing
: > and if the system needs to page something out to make the ram available
: > to you, you have a deadlock.
: 
: I wasn't sleeping.  This happened elsewhere as the result of a drive
: going away.  I had expected that the panic stack trace would point me
: at it, but it didn't.  I'll investigate further when I've fixed the
: current panic.

Malloc might sleep, and the above warning is that it might sleep.  You
can't hold mutexes and call malloc.  That's what that message is
saying.  Phk's explaination of what sleeping means is also correct,
even if you aren't actually sleeping.

Warner