linux/fs/fuse, branch v6.17

fuse: virtio_fs: fix page fault for DAX page address

2025-09-05T13:56:30Z

The commit ced17ee32a99 ("Revert "virtio: reject shm region if length is zero"") exposes the following DAX page fault bug (this fix the failure that getting shm region alway returns false because of zero length): The commit 21aa65bf82a7 ("mm: remove callers of pfn_t functionality") handles the DAX physical page address incorrectly: the removed macro 'phys_to_pfn_t()' should be replaced with 'PHYS_PFN()'. [ 1.390321] BUG: unable to handle page fault for address: ffffd3fb40000008 [ 1.390875] #PF: supervisor read access in kernel mode [ 1.391257] #PF: error_code(0x0000) - not-present page [ 1.391509] PGD 0 P4D 0 [ 1.391626] Oops: Oops: 0000 [#1] SMP NOPTI [ 1.391806] CPU: 6 UID: 1000 PID: 162 Comm: weston Not tainted 6.17.0-rc3-WSL2-STABLE #2 PREEMPT(none) [ 1.392361] RIP: 0010:dax_to_folio+0x14/0x60 [ 1.392653] Code: 52 c9 c3 00 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 48 c1 ef 05 48 c1 e7 06 48 03 3d 34 b5 31 01 <48> 8b 57 08 48 89 f8 f6 c2 01 75 2b 66 90 c3 cc cc cc cc f7 c7 ff [ 1.393727] RSP: 0000:ffffaf7d04407aa8 EFLAGS: 00010086 [ 1.394003] RAX: 000000a000000000 RBX: ffffaf7d04407bb0 RCX: 0000000000000000 [ 1.394524] RDX: ffffd17b40000008 RSI: 0000000000000083 RDI: ffffd3fb40000000 [ 1.394967] RBP: 0000000000000011 R08: 000000a000000000 R09: 0000000000000000 [ 1.395400] R10: 0000000000001000 R11: ffffaf7d04407c10 R12: 0000000000000000 [ 1.395806] R13: ffffa020557be9c0 R14: 0000014000000001 R15: 0000725970e94000 [ 1.396268] FS: 000072596d6d2ec0(0000) GS:ffffa0222dc59000(0000) knlGS:0000000000000000 [ 1.396715] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1.397100] CR2: ffffd3fb40000008 CR3: 000000011579c005 CR4: 0000000000372ef0 [ 1.397518] Call Trace: [ 1.397663] [ 1.397900] dax_insert_entry+0x13b/0x390 [ 1.398179] dax_fault_iter+0x2a5/0x6c0 [ 1.398443] dax_iomap_pte_fault+0x193/0x3c0 [ 1.398750] __fuse_dax_fault+0x8b/0x270 [ 1.398997] ? vm_mmap_pgoff+0x161/0x210 [ 1.399175] __do_fault+0x30/0x180 [ 1.399360] do_fault+0xc4/0x550 [ 1.399547] __handle_mm_fault+0x8e3/0xf50 [ 1.399731] ? do_syscall_64+0x72/0x1e0 [ 1.399958] handle_mm_fault+0x192/0x2f0 [ 1.400204] do_user_addr_fault+0x20e/0x700 [ 1.400418] exc_page_fault+0x66/0x150 [ 1.400602] asm_exc_page_fault+0x26/0x30 [ 1.400831] RIP: 0033:0x72596d1bf703 [ 1.401076] Code: 31 f6 45 31 e4 48 8d 15 b3 73 00 00 e8 06 03 00 00 8b 83 68 01 00 00 e9 8e fa ff ff 0f 1f 00 48 8b 44 24 08 4c 89 ee 48 89 df 00 21 43 34 12 e8 72 09 00 00 e9 6a fa ff ff 0f 1f 44 00 00 e8 [ 1.402172] RSP: 002b:00007ffc350f6dc0 EFLAGS: 00010202 [ 1.402488] RAX: 0000725970e94000 RBX: 00005b7c642c2560 RCX: 0000725970d359a7 [ 1.402898] RDX: 0000000000000003 RSI: 00007ffc350f6dc0 RDI: 00005b7c642c2560 [ 1.403284] RBP: 00007ffc350f6e90 R08: 000000000000000d R09: 0000000000000000 [ 1.403634] R10: 00007ffc350f6dd8 R11: 0000000000000246 R12: 0000000000000001 [ 1.404078] R13: 00007ffc350f6dc0 R14: 0000725970e29ce0 R15: 0000000000000003 [ 1.404450] [ 1.404570] Modules linked in: [ 1.404821] CR2: ffffd3fb40000008 [ 1.405029] ---[ end trace 0000000000000000 ]--- [ 1.405323] RIP: 0010:dax_to_folio+0x14/0x60 [ 1.405556] Code: 52 c9 c3 00 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 48 c1 ef 05 48 c1 e7 06 48 03 3d 34 b5 31 01 <48> 8b 57 08 48 89 f8 f6 c2 01 75 2b 66 90 c3 cc cc cc cc f7 c7 ff [ 1.406639] RSP: 0000:ffffaf7d04407aa8 EFLAGS: 00010086 [ 1.406910] RAX: 000000a000000000 RBX: ffffaf7d04407bb0 RCX: 0000000000000000 [ 1.407379] RDX: ffffd17b40000008 RSI: 0000000000000083 RDI: ffffd3fb40000000 [ 1.407800] RBP: 0000000000000011 R08: 000000a000000000 R09: 0000000000000000 [ 1.408246] R10: 0000000000001000 R11: ffffaf7d04407c10 R12: 0000000000000000 [ 1.408666] R13: ffffa020557be9c0 R14: 0000014000000001 R15: 0000725970e94000 [ 1.409170] FS: 000072596d6d2ec0(0000) GS:ffffa0222dc59000(0000) knlGS:0000000000000000 [ 1.409608] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1.409977] CR2: ffffd3fb40000008 CR3: 000000011579c005 CR4: 0000000000372ef0 [ 1.410437] Kernel panic - not syncing: Fatal exception [ 1.410857] Kernel Offset: 0xc000000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) Fixes: 21aa65bf82a7 ("mm: remove callers of pfn_t functionality") Signed-off-by: Haiyue Wang Link: https://lore.kernel.org/20250904120339.972-1-haiyuewa@163.com Acked-by: David Hildenbrand Reviewed-by: Miklos Szeredi Signed-off-by: Christian Brauner

fuse: Block access to folio overlimit

2025-08-27T12:29:43Z

syz reported a slab-out-of-bounds Write in fuse_dev_do_write. When the number of bytes to be retrieved is truncated to the upper limit by fc->max_pages and there is an offset, the oob is triggered. Add a loop termination condition to prevent overruns. Fixes: 3568a9569326 ("fuse: support large folios for retrieves") Reported-by: syzbot+2d215d165f9354b9c4ea@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=2d215d165f9354b9c4ea Tested-by: syzbot+2d215d165f9354b9c4ea@syzkaller.appspotmail.com Signed-off-by: Edward Adam Davis Reviewed-by: Joanne Koong Signed-off-by: Miklos Szeredi

fuse: fix fuseblk i_blkbits for iomap partial writes

2025-08-26T10:43:31Z

On regular fuse filesystems, i_blkbits is set to PAGE_SHIFT which means any iomap partial writes will mark the entire folio as uptodate. However fuseblk filesystems work differently and allow the blocksize to be less than the page size. As such, this may lead to data corruption if fuseblk sets its blocksize to less than the page size, uses the writeback cache, and does a partial write, then a read and the read happens before the write has undergone writeback, since the folio will not be marked uptodate from the partial write so the read will read in the entire folio from disk, which will overwrite the partial write. The long-term solution for this, which will also be needed for fuse to enable large folios with the writeback cache on, is to have fuse also use iomap for folio reads, but until that is done, the cleanest workaround is to use the page size for fuseblk's internal kernel inode blksize/blkbits values while maintaining current behavior for stat(). This was verified using ntfs-3g: $ sudo mkfs.ntfs -f -c 512 /dev/vdd1 $ sudo ntfs-3g /dev/vdd1 ~/fuseblk $ stat ~/fuseblk/hi.txt IO Block: 512 Fixes: a4c9ab1d4975 ("fuse: use iomap for buffered writes") Signed-off-by: Joanne Koong Reviewed-by: Darrick J. Wong Signed-off-by: Miklos Szeredi

fuse: reflect cached blocksize if blocksize was changed

2025-08-26T10:43:31Z

As pointed out by Miklos[1], in the fuse_update_get_attr() path, the attributes returned to stat may be cached values instead of fresh ones fetched from the server. In the case where the server returned a modified blocksize value, we need to cache it and reflect it back to stat if values are not re-fetched since we now no longer directly change inode->i_blkbits. Link: https://lore.kernel.org/linux-fsdevel/CAJfpeguCOxeVX88_zPd1hqziB_C+tmfuDhZP5qO2nKmnb-dTUA@mail.gmail.com/ [1] Fixes: 542ede096e48 ("fuse: keep inode->i_blkbits constant") Signed-off-by: Joanne Koong Reviewed-by: Darrick J. Wong Signed-off-by: Miklos Szeredi

fuse: prevent overflow in copy_file_range return value

2025-08-26T10:43:31Z

The FUSE protocol uses struct fuse_write_out to convey the return value of copy_file_range, which is restricted to uint32_t. But the COPY_FILE_RANGE interface supports a 64-bit size copies. Currently the number of bytes copied is silently truncated to 32-bit, which may result in poor performance or even failure to copy in case of truncation to zero. Reported-by: Florian Weimer Closes: https://lore.kernel.org/all/lhuh5ynl8z5.fsf@oldenburg.str.redhat.com/ Fixes: 88bc7d5097a1 ("fuse: add support for copy_file_range()") Cc: # v4.20 Signed-off-by: Miklos Szeredi

fuse: check if copy_file_range() returns larger than requested size

2025-08-26T10:43:31Z

Just like write(), copy_file_range() should check if the return value is less or equal to the requested number of bytes. Reported-by: Chunsheng Luo Closes: https://lore.kernel.org/all/20250807062425.694-1-luochunsheng@ustc.edu/ Fixes: 88bc7d5097a1 ("fuse: add support for copy_file_range()") Cc: # v4.20 Signed-off-by: Miklos Szeredi

fuse: do not allow mapping a non-regular backing file

2025-08-26T10:43:31Z

We do not support passthrough operations other than read/write on regular file, so allowing non-regular backing files makes no sense. Fixes: efad7153bf93 ("fuse: allow O_PATH fd for FUSE_DEV_IOC_BACKING_OPEN") Cc: stable@vger.kernel.org Signed-off-by: Amir Goldstein Reviewed-by: Bernd Schubert Signed-off-by: Miklos Szeredi

fuse: keep inode->i_blkbits constant

2025-08-11T12:51:50Z

With fuse now using iomap for writeback handling, inode blkbits changes are problematic because iomap relies on inode->i_blkbits for its internal bitmap logic. Currently we change inode->i_blkbits in fuse to match the attr->blksize value passed in by the server. This commit keeps inode->i_blkbits constant in fuse. Any attr->blksize values passed in by the server will not update inode->i_blkbits. The client-side behavior for stat is unaffected, stat will still reflect the blocksize passed in by the server. Signed-off-by: Joanne Koong Link: https://lore.kernel.org/20250807175015.515192-1-joannelkoong@gmail.com Fixes: ef7e7cbb32 ("fuse: use iomap for writeback") Signed-off-by: Christian Brauner

Merge tag 'mm-stable-2025-07-30-15-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-07-31T21:57:54Z

Pull MM updates from Andrew Morton: "As usual, many cleanups. The below blurbiage describes 42 patchsets. 21 of those are partially or fully cleanup work. "cleans up", "cleanup", "maintainability", "rationalizes", etc. I never knew the MM code was so dirty. "mm: ksm: prevent KSM from breaking merging of new VMAs" (Lorenzo Stoakes) addresses an issue with KSM's PR_SET_MEMORY_MERGE mode: newly mapped VMAs were not eligible for merging with existing adjacent VMAs. "mm/damon: introduce DAMON_STAT for simple and practical access monitoring" (SeongJae Park) adds a new kernel module which simplifies the setup and usage of DAMON in production environments. "stop passing a writeback_control to swap/shmem writeout" (Christoph Hellwig) is a cleanup to the writeback code which removes a couple of pointers from struct writeback_control. "drivers/base/node.c: optimization and cleanups" (Donet Tom) contains largely uncorrelated cleanups to the NUMA node setup and management code. "mm: userfaultfd: assorted fixes and cleanups" (Tal Zussman) does some maintenance work on the userfaultfd code. "Readahead tweaks for larger folios" (Ryan Roberts) implements some tuneups for pagecache readahead when it is reading into order>0 folios. "selftests/mm: Tweaks to the cow test" (Mark Brown) provides some cleanups and consistency improvements to the selftests code. "Optimize mremap() for large folios" (Dev Jain) does that. A 37% reduction in execution time was measured in a memset+mremap+munmap microbenchmark. "Remove zero_user()" (Matthew Wilcox) expunges zero_user() in favor of the more modern memzero_page(). "mm/huge_memory: vmf_insert_folio_*() and vmf_insert_pfn_pud() fixes" (David Hildenbrand) addresses some warts which David noticed in the huge page code. These were not known to be causing any issues at this time. "mm/damon: use alloc_migrate_target() for DAMOS_MIGRATE_{HOT,COLD" (SeongJae Park) provides some cleanup and consolidation work in DAMON. "use vm_flags_t consistently" (Lorenzo Stoakes) uses vm_flags_t in places where we were inappropriately using other types. "mm/memfd: Reserve hugetlb folios before allocation" (Vivek Kasireddy) increases the reliability of large page allocation in the memfd code. "mm: Remove pXX_devmap page table bit and pfn_t type" (Alistair Popple) removes several now-unneeded PFN_* flags. "mm/damon: decouple sysfs from core" (SeongJae Park) implememnts some cleanup and maintainability work in the DAMON sysfs layer. "madvise cleanup" (Lorenzo Stoakes) does quite a lot of cleanup/maintenance work in the madvise() code. "madvise anon_name cleanups" (Vlastimil Babka) provides additional cleanups on top or Lorenzo's effort. "Implement numa node notifier" (Oscar Salvador) creates a standalone notifier for NUMA node memory state changes. Previously these were lumped under the more general memory on/offline notifier. "Make MIGRATE_ISOLATE a standalone bit" (Zi Yan) cleans up the pageblock isolation code and fixes a potential issue which doesn't seem to cause any problems in practice. "selftests/damon: add python and drgn based DAMON sysfs functionality tests" (SeongJae Park) adds additional drgn- and python-based DAMON selftests which are more comprehensive than the existing selftest suite. "Misc rework on hugetlb faulting path" (Oscar Salvador) fixes a rather obscure deadlock in the hugetlb fault code and follows that fix with a series of cleanups. "cma: factor out allocation logic from __cma_declare_contiguous_nid" (Mike Rapoport) rationalizes and cleans up the highmem-specific code in the CMA allocator. "mm/migration: rework movable_ops page migration (part 1)" (David Hildenbrand) provides cleanups and future-preparedness to the migration code. "mm/damon: add trace events for auto-tuned monitoring intervals and DAMOS quota" (SeongJae Park) adds some tracepoints to some DAMON auto-tuning code. "mm/damon: fix misc bugs in DAMON modules" (SeongJae Park) does that. "mm/damon: misc cleanups" (SeongJae Park) also does what it claims. "mm: folio_pte_batch() improvements" (David Hildenbrand) cleans up the large folio PTE batching code. "mm/damon/vaddr: Allow interleaving in migrate_{hot,cold} actions" (SeongJae Park) facilitates dynamic alteration of DAMON's inter-node allocation policy. "Remove unmap_and_put_page()" (Vishal Moola) provides a couple of page->folio conversions. "mm: per-node proactive reclaim" (Davidlohr Bueso) implements a per-node control of proactive reclaim - beyond the current memcg-based implementation. "mm/damon: remove damon_callback" (SeongJae Park) replaces the damon_callback interface with a more general and powerful damon_call()+damos_walk() interface. "mm/mremap: permit mremap() move of multiple VMAs" (Lorenzo Stoakes) implements a number of mremap cleanups (of course) in preparation for adding new mremap() functionality: newly permit the remapping of multiple VMAs when the user is specifying MREMAP_FIXED. It still excludes some specialized situations where this cannot be performed reliably. "drop hugetlb_free_pgd_range()" (Anthony Yznaga) switches some sparc hugetlb code over to the generic version and removes the thus-unneeded hugetlb_free_pgd_range(). "mm/damon/sysfs: support periodic and automated stats update" (SeongJae Park) augments the present userspace-requested update of DAMON sysfs monitoring files. Automatic update is now provided, along with a tunable to control the update interval. "Some randome fixes and cleanups to swapfile" (Kemeng Shi) does what is claims. "mm: introduce snapshot_page" (Luiz Capitulino and David Hildenbrand) provides (and uses) a means by which debug-style functions can grab a copy of a pageframe and inspect it locklessly without tripping over the races inherent in operating on the live pageframe directly. "use per-vma locks for /proc/pid/maps reads" (Suren Baghdasaryan) addresses the large contention issues which can be triggered by reads from that procfs file. Latencies are reduced by more than half in some situations. The series also introduces several new selftests for the /proc/pid/maps interface. "__folio_split() clean up" (Zi Yan) cleans up __folio_split()! "Optimize mprotect() for large folios" (Dev Jain) provides some quite large (>3x) speedups to mprotect() when dealing with large folios. "selftests/mm: reuse FORCE_READ to replace "asm volatile("" : "+r" (XXX));" and some cleanup" (wang lian) does some cleanup work in the selftests code. "tools/testing: expand mremap testing" (Lorenzo Stoakes) extends the mremap() selftest in several ways, including adding more checking of Lorenzo's recently added "permit mremap() move of multiple VMAs" feature. "selftests/damon/sysfs.py: test all parameters" (SeongJae Park) extends the DAMON sysfs interface selftest so that it tests all possible user-requested parameters. Rather than the present minimal subset" * tag 'mm-stable-2025-07-30-15-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (370 commits) MAINTAINERS: add missing headers to mempory policy & migration section MAINTAINERS: add missing file to cgroup section MAINTAINERS: add MM MISC section, add missing files to MISC and CORE MAINTAINERS: add missing zsmalloc file MAINTAINERS: add missing files to page alloc section MAINTAINERS: add missing shrinker files MAINTAINERS: move memremap.[ch] to hotplug section MAINTAINERS: add missing mm_slot.h file THP section MAINTAINERS: add missing interval_tree.c to memory mapping section MAINTAINERS: add missing percpu-internal.h file to per-cpu section mm/page_alloc: remove trace_mm_alloc_contig_migrate_range_info() selftests/damon: introduce _common.sh to host shared function selftests/damon/sysfs.py: test runtime reduction of DAMON parameters selftests/damon/sysfs.py: test non-default parameters runtime commit selftests/damon/sysfs.py: generalize DAMON context commit assertion selftests/damon/sysfs.py: generalize monitoring attributes commit assertion selftests/damon/sysfs.py: generalize DAMOS schemes commit assertion selftests/damon/sysfs.py: test DAMOS filters commitment selftests/damon/sysfs.py: generalize DAMOS scheme commit assertion selftests/damon/sysfs.py: test DAMOS destinations commitment ...

Merge tag 'for-6.17/block-20250728' of git://git.kernel.dk/linux

2025-07-28T23:43:54Z

Pull block updates from Jens Axboe: - MD pull request via Yu: - call del_gendisk synchronously (Xiao) - cleanup unused variable (John) - cleanup workqueue flags (Ryo) - fix faulty rdev can't be removed during resync (Qixing) - NVMe pull request via Christoph: - try PCIe function level reset on init failure (Keith Busch) - log TLS handshake failures at error level (Maurizio Lombardi) - pci-epf: do not complete commands twice if nvmet_req_init() fails (Rick Wertenbroek) - misc cleanups (Alok Tiwari) - Removal of the pktcdvd driver This has been more than a decade coming at this point, and some recently revealed breakages that had it causing issues even for cases where it isn't required made me re-pull the trigger on this one. It's known broken and nobody has stepped up to maintain the code - Series for ublk supporting batch commands, enabling the use of multishot where appropriate - Speed up ublk exit handling - Fix for the two-stage elevator fixing which could leak data - Convert NVMe to use the new IOVA based API - Increase default max transfer size to something more reasonable - Series fixing write operations on zoned DM devices - Add tracepoints for zoned block device operations - Prep series working towards improving blk-mq queue management in the presence of isolated CPUs - Don't allow updating of the block size of a loop device that is currently under exclusively ownership/open - Set chunk sectors from stacked device stripe size and use it for the atomic write size limit - Switch to folios in bcache read_super() - Fix for CD-ROM MRW exit flush handling - Various tweaks, fixes, and cleanups * tag 'for-6.17/block-20250728' of git://git.kernel.dk/linux: (94 commits) block: restore two stage elevator switch while running nr_hw_queue update cdrom: Call cdrom_mrw_exit from cdrom_release function sunvdc: Balance device refcount in vdc_port_mpgroup_check nvme-pci: try function level reset on init failure dm: split write BIOs on zone boundaries when zone append is not emulated block: use chunk_sectors when evaluating stacked atomic write limits dm-stripe: limit chunk_sectors to the stripe size md/raid10: set chunk_sectors limit md/raid0: set chunk_sectors limit block: sanitize chunk_sectors for atomic write limits ilog2: add max_pow_of_two_factor() nvmet: pci-epf: Do not complete commands twice if nvmet_req_init() fails nvme-tcp: log TLS handshake failures at error level docs: nvme: fix grammar in nvme-pci-endpoint-target.rst nvme: fix typo in status code constant for self-test in progress nvmet: remove redundant assignment of error code in nvmet_ns_enable() nvme: fix incorrect variable in io cqes error message nvme: fix multiple spelling and grammar issues in host drivers block: fix blk_zone_append_update_request_bio() kernel-doc md/raid10: fix set but not used variable in sync_request_write() ...