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 ? Jason
