On Wed, 2015-09-09 at 15:03 -0700, Nicholas A. Bellinger wrote: > On Wed, 2015-09-09 at 19:59 +0530, Chaitra Basappa wrote: > > From: Sreekanth Reddy [mailto:sreekanth.reddy@xxxxxxxxxxxxx] > > Sent: Tuesday, September 08, 2015 5:26 PM > > To: Nicholas A. Bellinger > > Cc: linux-scsi; linux-kernel; James Bottomley; Calvin Owens; Christoph > > Hellwig; MPT-FusionLinux.pdl; kernel-team; Nicholas Bellinger; Chaitra > > Basappa > > Subject: Re: [PATCH-v2 1/2] mpt3sas: Refcount sas_device objects and fix > > unsafe list usage > > > > On Sun, Aug 30, 2015 at 1:24 PM, Nicholas A. Bellinger <nab@xxxxxxxxxxxxx> > > wrote: > > > From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> > > > > > > These objects can be referenced concurrently throughout the driver, we > > > need a way to make sure threads can't delete them out from under each > > > other. This patch adds the refcount, and refactors the code to use it. > > > > > > Additionally, we cannot iterate over the sas_device_list without > > > holding the lock, or we risk corrupting random memory if items are > > > added or deleted as we iterate. This patch refactors > > > _scsih_probe_sas() to use the sas_device_list in a safe way. > > > > > > This patch is a port of Calvin's PATCH-v4 for mpt2sas code, atop > > > mpt3sas changes in scsi.git/for-next. > > > > > > Cc: Calvin Owens <calvinowens@xxxxxx> > > > Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx> > > > Cc: Sreekanth Reddy <sreekanth.reddy@xxxxxxxxxxxxx> > > > Cc: MPT-FusionLinux.pdl <MPT-FusionLinux.pdl@xxxxxxxxxxxxx> > > > Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> > > > --- > > > drivers/scsi/mpt3sas/mpt3sas_base.h | 25 +- > > > drivers/scsi/mpt3sas/mpt3sas_scsih.c | 479 > > > +++++++++++++++++++++---------- > > > drivers/scsi/mpt3sas/mpt3sas_transport.c | 18 +- > > > 3 files changed, 364 insertions(+), 158 deletions(-) > > > > > > @@ -2763,7 +2874,7 @@ _scsih_block_io_device(struct MPT3SAS_ADAPTER *ioc, > > > u16 handle) > > > struct scsi_device *sdev; > > > struct _sas_device *sas_device; > > > > > > > [Sreekanth] Here sas_device_lock spin lock needs to be acquired before > > calling > > __mpt3sas_get_sdev_by_addr() function. > > > > [Chaitra]Here instead of calling " __mpt3sas_get_sdev_by_handle()" function > > calling > > "mpt3sas_get_sdev_by_handle()" function will fixes "invalid page access" > > type of kernel panic > > > > > - sas_device = _scsih_sas_device_find_by_handle(ioc, handle); > > > + sas_device = __mpt3sas_get_sdev_by_handle(ioc, handle); > > > if (!sas_device) > > > return; > > > > > Whoops, missed this comment in _scsih_block_io_device() from Sreekanth's > earlier reply. > > Here's the updated incremental patch atop target-pending/for-next-merge > to use the protected callers for both cases. > > Please review + ACK ASAP. The mpt3sas -v2 series + v4.3-rc0 breakage incremental patch here made it into linux-next-09102015, and at this point I don't see a scenario where keeping around the broken list_head dereferences makes sense. So that said, I'd like to send a target-pending/for-next-merge PULL request out to Linus in the next 48 hours. Any objections from Avago folks..? Thank you, --nab -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
