On 12/03/2011 11:07 PM, Steffen Maier wrote: > On 12/02/2011 04:26 PM, Stratos Psomadakis wrote: >> After upstream commit 4e6c82b3614a18740ef63109d58743a359266daf ([SCSI] >> fix WARNING: at drivers/scsi/scsi_lib.c:1704), which is also included in >> 3.0-stable and 3.1-stable kernels, the kernel fails to boot (NULL >> pointer dereference in sym53c8xx_slave_destroy). >> >> Bug report at the Gentoo Bugzilla (reported and bisected by Martin von >> Gagern). [1] (stack trace [2]) >> >> I think that the problem is that (after commit 4e6c82b) >> __scsi_remove_device() is called if slave_alloc() in scsi_alloc_sdev() >> fails. But __scsi_remove_device() calls slave_destroy(), which (I think) >> doesn't make much sense (ie to call slave_destroy() when slave_alloc() >> fails). >> >> For sym53c8xx, this results in a NULL pointer dereference (struct >> sym_lcb pointer) in slave_destroy(). >> >> [1] https://bugs.gentoo.org/show_bug.cgi?id=392567 >> [2] https://392567.bugs.gentoo.org/attachment.cgi?id=294381 > > To me this looks like the same thing we encountered in the zfcp LLD: > http://www.spinics.net/lists/linux-scsi/msg55575.html > James explained the pairing of slave_alloc and slave_destroy even if > slave_alloc returned early in which case slave_destroy needs to cope > with that: > http://www.spinics.net/lists/linux-scsi/msg55449.html > Indeed. I'll follow-up with a patch similar to the one you sent for zfcp. I think that returning if sym_lcb is NULL should be ok. > HTH > Steffen > > Linux on System z Development > > IBM Deutschland Research & Development GmbH > Vorsitzender des Aufsichtsrats: Martin Jetter > Geschäftsführung: Dirk Wittkopp > Sitz der Gesellschaft: Böblingen > Registergericht: Amtsgericht Stuttgart, HRB 243294 > > -- > To unsubscribe from this list: send the line "unsubscribe > linux-kernel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- Stratos Psomadakis <psomas@xxxxxxxxxx>
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