Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1322194
| From | Dan Williams <dan.j.williams@intel.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences |
| Date | 2016-01-30 01:20 +0100 |
| Message-ID | <qWrqG-2GF-5@gated-at.bofh.it> (permalink) |
| References | <qW0A9-87S-3@gated-at.bofh.it> <qW0A9-87S-1@gated-at.bofh.it> <qW2sh-Yt-1@gated-at.bofh.it> <qWlXY-79P-15@gated-at.bofh.it> <qWqNY-29Q-5@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Fri, Jan 29, 2016 at 3:34 PM, Ross Zwisler <ross.zwisler@linux.intel.com> wrote: > On Fri, Jan 29, 2016 at 11:28:15AM -0700, Ross Zwisler wrote: >> On Thu, Jan 28, 2016 at 01:38:58PM -0800, Christoph Hellwig wrote: >> > On Thu, Jan 28, 2016 at 12:35:04PM -0700, Ross Zwisler wrote: >> > > There are a number of places in dax.c that look up the struct block_device >> > > associated with an inode. Previously this was done by just using >> > > inode->i_sb->s_bdev. This is correct for inodes that exist within the >> > > filesystems supported by DAX (ext2, ext4 & XFS), but when running DAX >> > > against raw block devices this value is NULL. This causes NULL pointer >> > > dereferences when these block_device pointers are used. >> > >> > It's also wrong for an XFS file system with a RT device.. >> > >> > > +#define DAX_BDEV(inode) (S_ISBLK(inode->i_mode) ? I_BDEV(inode) \ >> > > + : inode->i_sb->s_bdev) >> > >> > .. but this isn't going to fix it. You must use a bdev returned by >> > get_blocks or a similar file system method. >> >> I guess I need to go off and understand if we can have DAX mappings on such a >> device. If we can, we may have a problem - we can get the block_device from >> get_block() in I/O path and the various fault paths, but we don't have access >> to get_block() when flushing via dax_writeback_mapping_range(). We avoid >> needing it the normal case by storing the sector results from get_block() in >> the radix tree. >> >> /me is off to play with RT devices... > > Well, RT devices are completely broken as far as I can see. I've reported the > breakage to the XFS list. Anything I do that triggers a RT block allocation > in XFS causes a lockdep splat + a kernel BUG - I've tried regular pwrite(), > xfs_rtcp and mmap() + write to address. Not a new bug either - happens just > the same with v4.4. Happens with both PMEM and BRD, and has no relationship > to whether I'm using DAX or not. > > Does it work for this patch to go in as-is since it fixes an immediate OOPS > with raw block devices + DAX, and when RT devices are alive again I'll figure > out how to make them work too? Can we step back and be clear about which lookups should be coming from get_blocks(). Which ones are critical vs ones we just opportunistically lookup for a debug print. Right now xfs and ext4 are basically disagreeing on whether get_blocks() reliably sets ->bh_bdev, and checking for a raw block-device inode in dax_clear_blocks() does not make sense. So this all seems a bit confused.
Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
[PATCH 2/2] dax: fix bdev NULL pointer dereferences Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-01-28 20:40 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Dan Williams <dan.j.williams@intel.com> - 2016-01-28 21:30 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Christoph Hellwig <hch@infradead.org> - 2016-01-28 22:40 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-01-29 19:30 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-01-30 00:40 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Dan Williams <dan.j.williams@intel.com> - 2016-01-30 01:20 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Dave Chinner <david@fromorbit.com> - 2016-01-31 23:50 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Matthew Wilcox <willy@linux.intel.com> - 2016-01-30 06:30 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Dan Williams <dan.j.williams@intel.com> - 2016-01-30 07:10 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Jared Hulbert <jaredeh@gmail.com> - 2016-01-30 08:10 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Matthew Wilcox <willy@linux.intel.com> - 2016-01-31 03:40 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Ross Zwisler <zwisler@gmail.com> - 2016-01-31 07:20 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Matthew Wilcox <willy@linux.intel.com> - 2016-01-31 12:00 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Dan Williams <dan.j.williams@intel.com> - 2016-01-31 17:40 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Matthew Wilcox <willy@linux.intel.com> - 2016-01-31 19:10 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Dan Williams <dan.j.williams@intel.com> - 2016-01-31 19:20 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Matthew Wilcox <willy@linux.intel.com> - 2016-01-31 19:30 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Dan Williams <dan.j.williams@intel.com> - 2016-01-31 20:00 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Dan Williams <dan.j.williams@intel.com> - 2016-01-31 21:00 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Jan Kara <jack@suse.cz> - 2016-02-01 16:00 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Matthew Wilcox <willy@linux.intel.com> - 2016-02-01 21:50 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Dave Chinner <david@fromorbit.com> - 2016-02-01 22:50 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Jared Hulbert <jaredeh@gmail.com> - 2016-02-02 07:10 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Dan Williams <dan.j.williams@intel.com> - 2016-02-02 07:50 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Jared Hulbert <jaredeh@gmail.com> - 2016-02-02 09:10 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Dan Williams <dan.j.williams@intel.com> - 2016-02-02 18:00 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Jared Hulbert <jaredeh@gmail.com> - 2016-02-02 22:50 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Matthew Wilcox <willy@linux.intel.com> - 2016-02-03 01:40 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Jared Hulbert <jaredeh@gmail.com> - 2016-02-03 02:30 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Jan Kara <jack@suse.cz> - 2016-02-02 12:20 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Dan Williams <dan.j.williams@intel.com> - 2016-02-02 17:40 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Jan Kara <jack@suse.cz> - 2016-02-02 17:50 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Dan Williams <dan.j.williams@intel.com> - 2016-02-02 18:20 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-02-02 18:40 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Dan Williams <dan.j.williams@intel.com> - 2016-02-02 18:50 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-02-02 19:30 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Dan Williams <dan.j.williams@intel.com> - 2016-02-02 18:50 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Matthew Wilcox <willy@linux.intel.com> - 2016-02-02 19:50 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Dan Williams <dan.j.williams@intel.com> - 2016-02-02 20:10 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Matthew Wilcox <willy@linux.intel.com> - 2016-02-02 21:20 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Jan Kara <jack@suse.cz> - 2016-02-03 12:10 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Jan Kara <jack@suse.cz> - 2016-02-03 11:50 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-02-03 21:20 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Jan Kara <jack@suse.cz> - 2016-02-04 10:20 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-02-05 00:40 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Dave Chinner <david@fromorbit.com> - 2016-02-07 00:20 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-02-07 06:30 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-02-04 21:00 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Jan Kara <jack@suse.cz> - 2016-02-04 21:40 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-02-04 23:20 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-02-05 23:30 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Dave Chinner <david@fromorbit.com> - 2016-02-07 00:50 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-02-07 07:50 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Jan Kara <jack@suse.cz> - 2016-02-08 14:50 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Christoph Hellwig <hch@infradead.org> - 2016-02-07 09:40 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-02-08 17:00 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-02-02 19:50 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-02-02 20:00 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Ross Zwisler <ross.zwisler@linux.intel.com> - 2016-02-02 01:10 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Dave Chinner <david@fromorbit.com> - 2016-02-02 08:20 +0100
Re: [PATCH 2/2] dax: fix bdev NULL pointer dereferences Jan Kara <jack@suse.cz> - 2016-02-02 11:40 +0100
csiph-web