On Thu, Jun 13, 2019 at 08:40:46PM +0000, Jason Gunthorpe wrote: > On Thu, Jun 13, 2019 at 11:27:39AM -0700, Dan Williams wrote: > > On Thu, Jun 13, 2019 at 2:43 AM Christoph Hellwig <hch@xxxxxx> wrote: > > > > > > Hi Dan, Jérôme and Jason, > > > > > > below is a series that cleans up the dev_pagemap interface so that > > > it is more easily usable, which removes the need to wrap it in hmm > > > and thus allowing to kill a lot of code > > > > > > Diffstat: > > > > > > 22 files changed, 245 insertions(+), 802 deletions(-) > > > > Hooray! > > > > > Git tree: > > > > > > git://git.infradead.org/users/hch/misc.git hmm-devmem-cleanup > > > > I just realized this collides with the dev_pagemap release rework in > > Andrew's tree (commit ids below are from next.git and are not stable) > > > > 4422ee8476f0 mm/devm_memremap_pages: fix final page put race > > 771f0714d0dc PCI/P2PDMA: track pgmap references per resource, not globally > > af37085de906 lib/genalloc: introduce chunk owners > > e0047ff8aa77 PCI/P2PDMA: fix the gen_pool_add_virt() failure path > > 0315d47d6ae9 mm/devm_memremap_pages: introduce devm_memunmap_pages > > 216475c7eaa8 drivers/base/devres: introduce devm_release_action() > > > > CONFLICT (content): Merge conflict in tools/testing/nvdimm/test/iomap.c > > CONFLICT (content): Merge conflict in mm/hmm.c > > CONFLICT (content): Merge conflict in kernel/memremap.c > > CONFLICT (content): Merge conflict in include/linux/memremap.h > > CONFLICT (content): Merge conflict in drivers/pci/p2pdma.c > > CONFLICT (content): Merge conflict in drivers/nvdimm/pmem.c > > CONFLICT (content): Merge conflict in drivers/dax/device.c > > CONFLICT (content): Merge conflict in drivers/dax/dax-private.h > > > > Perhaps we should pull those out and resend them through hmm.git? > > It could be done - but how bad is the conflict resolution? > > I'd be more comfortable to take a PR from you to merge into hmm.git, > rather than raw patches, then apply CH's series on top. I think. > > That way if something goes wrong you can send your PR to Linus > directly. > > > It also turns out the nvdimm unit tests crash with this signature on > > that branch where base v5.2-rc3 passes: > > > > BUG: kernel NULL pointer dereference, address: 0000000000000008 > > [..] > > CPU: 15 PID: 1414 Comm: lt-libndctl Tainted: G OE > > 5.2.0-rc3+ #3399 > > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015 > > RIP: 0010:percpu_ref_kill_and_confirm+0x1e/0x180 > > [..] > > Call Trace: > > release_nodes+0x234/0x280 > > device_release_driver_internal+0xe8/0x1b0 > > bus_remove_device+0xf2/0x160 > > device_del+0x166/0x370 > > unregister_dev_dax+0x23/0x50 > > release_nodes+0x234/0x280 > > device_release_driver_internal+0xe8/0x1b0 > > unbind_store+0x94/0x120 > > kernfs_fop_write+0xf0/0x1a0 > > vfs_write+0xb7/0x1b0 > > ksys_write+0x5c/0xd0 > > do_syscall_64+0x60/0x240 > > Too bad the trace didn't say which devm cleanup triggered it.. Did > dev_pagemap_percpu_exit get called with a NULL pgmap->ref ? I would guess something like that. I did not fully wrap my head around the ref counting there but I don't think the patch is correct. See my review. Ira > > Jason > _______________________________________________ > Linux-nvdimm mailing list > Linux-nvdimm@xxxxxxxxxxxx > https://lists.01.org/mailman/listinfo/linux-nvdimm
