Date: Mon, 19 Sep 2005 08:31:46 -0600 (MDT) From: "M. Warner Losh" <imp@bsdimp.com> To: ru@freebsd.org Cc: cvs-src@freebsd.org, src-committers@freebsd.org, cvs-all@freebsd.org Subject: Re: cvs commit: src/sys/dev/an if_an.c src/sys/dev/arl if_arl_isa.c src/sys/dev/awi if_awi_pccard.c src/sys/dev/cm if_cm_isa.c src/sys/dev/cnw if_cnw.c src/sys/dev/cp if_cp.c src/sys/dev/cs if_cs.c src/sys/dev/ed if_ed.c src/sys/dev/em if_em.c ... Message-ID: <20050919.083146.105425670.imp@bsdimp.com> In-Reply-To: <20050919055028.GC65954@ip.net.ua> References: <200509190310.j8J3ALgt095979@repoman.freebsd.org> <20050919055028.GC65954@ip.net.ua>
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In message: <20050919055028.GC65954@ip.net.ua>
Ruslan Ermilov <ru@freebsd.org> writes:
: Hi,
:
: On Mon, Sep 19, 2005 at 03:10:21AM +0000, Warner Losh wrote:
: > imp 2005-09-19 03:10:21 UTC
: >
: > FreeBSD src repository
: >
: > Modified files:
: > sys/dev/an if_an.c
: [...]
: > sys/dev/xe if_xe_pccard.c
: > Log:
: > Make sure that we call if_free(ifp) after bus_teardown_intr. Since we
: > could get an interrupt after we free the ifp, and the interrupt
: > handler depended on the ifp being still alive, this could, in theory,
: > cause a crash. Eliminate this possibility by moving the if_free to
: > after the bus_teardown_intr() call.
: >
: I'm going into more details in my other reply to your ed(4) commit,
: but I'm pretty sure you're attacking a wrong problem here. Most
: drivers don' assume and will behave badly (read: panic) if foo_intr()
: is called after foo_stop() (foo_stop() disables interrupts and
: usually frees some resources needed by code called from foo_intr()).
: A better fix that I had in mind (and that I think jhb@ has suggested)
: would be to return from foo_intr() quickly if IFF_DRV_RUNNING is not
: set. Can you reproduce the problem that you mention on real hardware?
You can't test IFF_DRV_RUNNING in memory that's already been freed.
Warner
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