linux.git/fs/jfs, branch v6.16 Linux kernel source tree Merge tag 'mm-stable-2025-05-31-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm 2025-05-31T22:44:16+00:00 Linus Torvalds torvalds@linux-foundation.org 2025-05-31T22:44:16+00:00 00c010e130e58301db2ea0cec1eadc931e1cb8cf Pull MM updates from Andrew Morton: - "Add folio_mk_pte()" from Matthew Wilcox simplifies the act of creating a pte which addresses the first page in a folio and reduces the amount of plumbing which architecture must implement to provide this. - "Misc folio patches for 6.16" from Matthew Wilcox is a shower of largely unrelated folio infrastructure changes which clean things up and better prepare us for future work. - "memory,x86,acpi: hotplug memory alignment advisement" from Gregory Price adds early-init code to prevent x86 from leaving physical memory unused when physical address regions are not aligned to memory block size. - "mm/compaction: allow more aggressive proactive compaction" from Michal Clapinski provides some tuning of the (sadly, hard-coded (more sadly, not auto-tuned)) thresholds for our invokation of proactive compaction. In a simple test case, the reduction of a guest VM's memory consumption was dramatic. - "Minor cleanups and improvements to swap freeing code" from Kemeng Shi provides some code cleaups and a small efficiency improvement to this part of our swap handling code. - "ptrace: introduce PTRACE_SET_SYSCALL_INFO API" from Dmitry Levin adds the ability for a ptracer to modify syscalls arguments. At this time we can alter only "system call information that are used by strace system call tampering, namely, syscall number, syscall arguments, and syscall return value. This series should have been incorporated into mm.git's "non-MM" branch, but I goofed. - "fs/proc: extend the PAGEMAP_SCAN ioctl to report guard regions" from Andrei Vagin extends the info returned by the PAGEMAP_SCAN ioctl against /proc/pid/pagemap. This permits CRIU to more efficiently get at the info about guard regions. - "Fix parameter passed to page_mapcount_is_type()" from Gavin Shan implements that fix. No runtime effect is expected because validate_page_before_insert() happens to fix up this error. - "kernel/events/uprobes: uprobe_write_opcode() rewrite" from David Hildenbrand basically brings uprobe text poking into the current decade. Remove a bunch of hand-rolled implementation in favor of using more current facilities. - "mm/ptdump: Drop assumption that pxd_val() is u64" from Anshuman Khandual provides enhancements and generalizations to the pte dumping code. This might be needed when 128-bit Page Table Descriptors are enabled for ARM. - "Always call constructor for kernel page tables" from Kevin Brodsky ensures that the ctor/dtor is always called for kernel pgtables, as it already is for user pgtables. This permits the addition of more functionality such as "insert hooks to protect page tables". This change does result in various architectures performing unnecesary work, but this is fixed up where it is anticipated to occur. - "Rust support for mm_struct, vm_area_struct, and mmap" from Alice Ryhl adds plumbing to permit Rust access to core MM structures. - "fix incorrectly disallowed anonymous VMA merges" from Lorenzo Stoakes takes advantage of some VMA merging opportunities which we've been missing for 15 years. - "mm/madvise: batch tlb flushes for MADV_DONTNEED and MADV_FREE" from SeongJae Park optimizes process_madvise()'s TLB flushing. Instead of flushing each address range in the provided iovec, we batch the flushing across all the iovec entries. The syscall's cost was approximately halved with a microbenchmark which was designed to load this particular operation. - "Track node vacancy to reduce worst case allocation counts" from Sidhartha Kumar makes the maple tree smarter about its node preallocation. stress-ng mmap performance increased by single-digit percentages and the amount of unnecessarily preallocated memory was dramaticelly reduced. - "mm/gup: Minor fix, cleanup and improvements" from Baoquan He removes a few unnecessary things which Baoquan noted when reading the code. - ""Enhance sysfs handling for memory hotplug in weighted interleave" from Rakie Kim "enhances the weighted interleave policy in the memory management subsystem by improving sysfs handling, fixing memory leaks, and introducing dynamic sysfs updates for memory hotplug support". Fixes things on error paths which we are unlikely to hit. - "mm/damon: auto-tune DAMOS for NUMA setups including tiered memory" from SeongJae Park introduces new DAMOS quota goal metrics which eliminate the manual tuning which is required when utilizing DAMON for memory tiering. - "mm/vmalloc.c: code cleanup and improvements" from Baoquan He provides cleanups and small efficiency improvements which Baoquan found via code inspection. - "vmscan: enforce mems_effective during demotion" from Gregory Price changes reclaim to respect cpuset.mems_effective during demotion when possible. because presently, reclaim explicitly ignores cpuset.mems_effective when demoting, which may cause the cpuset settings to violated. This is useful for isolating workloads on a multi-tenant system from certain classes of memory more consistently. - "Clean up split_huge_pmd_locked() and remove unnecessary folio pointers" from Gavin Guo provides minor cleanups and efficiency gains in in the huge page splitting and migrating code. - "Use kmem_cache for memcg alloc" from Huan Yang creates a slab cache for `struct mem_cgroup', yielding improved memory utilization. - "add max arg to swappiness in memory.reclaim and lru_gen" from Zhongkun He adds a new "max" argument to the "swappiness=" argument for memory.reclaim MGLRU's lru_gen. This directs proactive reclaim to reclaim from only anon folios rather than file-backed folios. - "kexec: introduce Kexec HandOver (KHO)" from Mike Rapoport is the first step on the path to permitting the kernel to maintain existing VMs while replacing the host kernel via file-based kexec. At this time only memblock's reserve_mem is preserved. - "mm: Introduce for_each_valid_pfn()" from David Woodhouse provides and uses a smarter way of looping over a pfn range. By skipping ranges of invalid pfns. - "sched/numa: Skip VMA scanning on memory pinned to one NUMA node via cpuset.mems" from Libo Chen removes a lot of pointless VMA scanning when a task is pinned a single NUMA mode. Dramatic performance benefits were seen in some real world cases. - "JFS: Implement migrate_folio for jfs_metapage_aops" from Shivank Garg addresses a warning which occurs during memory compaction when using JFS. - "move all VMA allocation, freeing and duplication logic to mm" from Lorenzo Stoakes moves some VMA code from kernel/fork.c into the more appropriate mm/vma.c. - "mm, swap: clean up swap cache mapping helper" from Kairui Song provides code consolidation and cleanups related to the folio_index() function. - "mm/gup: Cleanup memfd_pin_folios()" from Vishal Moola does that. - "memcg: Fix test_memcg_min/low test failures" from Waiman Long addresses some bogus failures which are being reported by the test_memcontrol selftest. - "eliminate mmap() retry merge, add .mmap_prepare hook" from Lorenzo Stoakes commences the deprecation of file_operations.mmap() in favor of the new file_operations.mmap_prepare(). The latter is more restrictive and prevents drivers from messing with things in ways which, amongst other problems, may defeat VMA merging. - "memcg: decouple memcg and objcg stocks"" from Shakeel Butt decouples the per-cpu memcg charge cache from the objcg's one. This is a step along the way to making memcg and objcg charging NMI-safe, which is a BPF requirement. - "mm/damon: minor fixups and improvements for code, tests, and documents" from SeongJae Park is yet another batch of miscellaneous DAMON changes. Fix and improve minor problems in code, tests and documents. - "memcg: make memcg stats irq safe" from Shakeel Butt converts memcg stats to be irq safe. Another step along the way to making memcg charging and stats updates NMI-safe, a BPF requirement. - "Let unmap_hugepage_range() and several related functions take folio instead of page" from Fan Ni provides folio conversions in the hugetlb code. * tag 'mm-stable-2025-05-31-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (285 commits) mm: pcp: increase pcp->free_count threshold to trigger free_high mm/hugetlb: convert use of struct page to folio in __unmap_hugepage_range() mm/hugetlb: refactor __unmap_hugepage_range() to take folio instead of page mm/hugetlb: refactor unmap_hugepage_range() to take folio instead of page mm/hugetlb: pass folio instead of page to unmap_ref_private() memcg: objcg stock trylock without irq disabling memcg: no stock lock for cpu hot-unplug memcg: make __mod_memcg_lruvec_state re-entrant safe against irqs memcg: make count_memcg_events re-entrant safe against irqs memcg: make mod_memcg_state re-entrant safe against irqs memcg: move preempt disable to callers of memcg_rstat_updated memcg: memcg_rstat_updated re-entrant safe against irqs mm: khugepaged: decouple SHMEM and file folios' collapse selftests/eventfd: correct test name and improve messages alloc_tag: check mem_profiling_support in alloc_tag_init Docs/damon: update titles and brief introductions to explain DAMOS selftests/damon/_damon_sysfs: read tried regions directories in order mm/damon/tests/core-kunit: add a test for damos_set_filters_default_reject() mm/damon/paddr: remove unused variable, folio_list, in damon_pa_stat() mm/damon/sysfs-schemes: fix wrong comment on damons_sysfs_quota_goal_metric_strs ... 
Pull MM updates from Andrew Morton:

 - "Add folio_mk_pte()" from Matthew Wilcox simplifies the act of
   creating a pte which addresses the first page in a folio and reduces
   the amount of plumbing which architecture must implement to provide
   this.

 - "Misc folio patches for 6.16" from Matthew Wilcox is a shower of
   largely unrelated folio infrastructure changes which clean things up
   and better prepare us for future work.

 - "memory,x86,acpi: hotplug memory alignment advisement" from Gregory
   Price adds early-init code to prevent x86 from leaving physical
   memory unused when physical address regions are not aligned to memory
   block size.

 - "mm/compaction: allow more aggressive proactive compaction" from
   Michal Clapinski provides some tuning of the (sadly, hard-coded (more
   sadly, not auto-tuned)) thresholds for our invokation of proactive
   compaction. In a simple test case, the reduction of a guest VM's
   memory consumption was dramatic.

 - "Minor cleanups and improvements to swap freeing code" from Kemeng
   Shi provides some code cleaups and a small efficiency improvement to
   this part of our swap handling code.

 - "ptrace: introduce PTRACE_SET_SYSCALL_INFO API" from Dmitry Levin
   adds the ability for a ptracer to modify syscalls arguments. At this
   time we can alter only "system call information that are used by
   strace system call tampering, namely, syscall number, syscall
   arguments, and syscall return value.

   This series should have been incorporated into mm.git's "non-MM"
   branch, but I goofed.

 - "fs/proc: extend the PAGEMAP_SCAN ioctl to report guard regions" from
   Andrei Vagin extends the info returned by the PAGEMAP_SCAN ioctl
   against /proc/pid/pagemap. This permits CRIU to more efficiently get
   at the info about guard regions.

 - "Fix parameter passed to page_mapcount_is_type()" from Gavin Shan
   implements that fix. No runtime effect is expected because
   validate_page_before_insert() happens to fix up this error.

 - "kernel/events/uprobes: uprobe_write_opcode() rewrite" from David
   Hildenbrand basically brings uprobe text poking into the current
   decade. Remove a bunch of hand-rolled implementation in favor of
   using more current facilities.

 - "mm/ptdump: Drop assumption that pxd_val() is u64" from Anshuman
   Khandual provides enhancements and generalizations to the pte dumping
   code. This might be needed when 128-bit Page Table Descriptors are
   enabled for ARM.

 - "Always call constructor for kernel page tables" from Kevin Brodsky
   ensures that the ctor/dtor is always called for kernel pgtables, as
   it already is for user pgtables.

   This permits the addition of more functionality such as "insert hooks
   to protect page tables". This change does result in various
   architectures performing unnecesary work, but this is fixed up where
   it is anticipated to occur.

 - "Rust support for mm_struct, vm_area_struct, and mmap" from Alice
   Ryhl adds plumbing to permit Rust access to core MM structures.

 - "fix incorrectly disallowed anonymous VMA merges" from Lorenzo
   Stoakes takes advantage of some VMA merging opportunities which we've
   been missing for 15 years.

 - "mm/madvise: batch tlb flushes for MADV_DONTNEED and MADV_FREE" from
   SeongJae Park optimizes process_madvise()'s TLB flushing.

   Instead of flushing each address range in the provided iovec, we
   batch the flushing across all the iovec entries. The syscall's cost
   was approximately halved with a microbenchmark which was designed to
   load this particular operation.

 - "Track node vacancy to reduce worst case allocation counts" from
   Sidhartha Kumar makes the maple tree smarter about its node
   preallocation.

   stress-ng mmap performance increased by single-digit percentages and
   the amount of unnecessarily preallocated memory was dramaticelly
   reduced.

 - "mm/gup: Minor fix, cleanup and improvements" from Baoquan He removes
   a few unnecessary things which Baoquan noted when reading the code.

 - ""Enhance sysfs handling for memory hotplug in weighted interleave"
   from Rakie Kim "enhances the weighted interleave policy in the memory
   management subsystem by improving sysfs handling, fixing memory
   leaks, and introducing dynamic sysfs updates for memory hotplug
   support". Fixes things on error paths which we are unlikely to hit.

 - "mm/damon: auto-tune DAMOS for NUMA setups including tiered memory"
   from SeongJae Park introduces new DAMOS quota goal metrics which
   eliminate the manual tuning which is required when utilizing DAMON
   for memory tiering.

 - "mm/vmalloc.c: code cleanup and improvements" from Baoquan He
   provides cleanups and small efficiency improvements which Baoquan
   found via code inspection.

 - "vmscan: enforce mems_effective during demotion" from Gregory Price
   changes reclaim to respect cpuset.mems_effective during demotion when
   possible. because presently, reclaim explicitly ignores
   cpuset.mems_effective when demoting, which may cause the cpuset
   settings to violated.

   This is useful for isolating workloads on a multi-tenant system from
   certain classes of memory more consistently.

 - "Clean up split_huge_pmd_locked() and remove unnecessary folio
   pointers" from Gavin Guo provides minor cleanups and efficiency gains
   in in the huge page splitting and migrating code.

 - "Use kmem_cache for memcg alloc" from Huan Yang creates a slab cache
   for `struct mem_cgroup', yielding improved memory utilization.

 - "add max arg to swappiness in memory.reclaim and lru_gen" from
   Zhongkun He adds a new "max" argument to the "swappiness=" argument
   for memory.reclaim MGLRU's lru_gen.

   This directs proactive reclaim to reclaim from only anon folios
   rather than file-backed folios.

 - "kexec: introduce Kexec HandOver (KHO)" from Mike Rapoport is the
   first step on the path to permitting the kernel to maintain existing
   VMs while replacing the host kernel via file-based kexec. At this
   time only memblock's reserve_mem is preserved.

 - "mm: Introduce for_each_valid_pfn()" from David Woodhouse provides
   and uses a smarter way of looping over a pfn range. By skipping
   ranges of invalid pfns.

 - "sched/numa: Skip VMA scanning on memory pinned to one NUMA node via
   cpuset.mems" from Libo Chen removes a lot of pointless VMA scanning
   when a task is pinned a single NUMA mode.

   Dramatic performance benefits were seen in some real world cases.

 - "JFS: Implement migrate_folio for jfs_metapage_aops" from Shivank
   Garg addresses a warning which occurs during memory compaction when
   using JFS.

 - "move all VMA allocation, freeing and duplication logic to mm" from
   Lorenzo Stoakes moves some VMA code from kernel/fork.c into the more
   appropriate mm/vma.c.

 - "mm, swap: clean up swap cache mapping helper" from Kairui Song
   provides code consolidation and cleanups related to the folio_index()
   function.

 - "mm/gup: Cleanup memfd_pin_folios()" from Vishal Moola does that.

 - "memcg: Fix test_memcg_min/low test failures" from Waiman Long
   addresses some bogus failures which are being reported by the
   test_memcontrol selftest.

 - "eliminate mmap() retry merge, add .mmap_prepare hook" from Lorenzo
   Stoakes commences the deprecation of file_operations.mmap() in favor
   of the new file_operations.mmap_prepare().

   The latter is more restrictive and prevents drivers from messing with
   things in ways which, amongst other problems, may defeat VMA merging.

 - "memcg: decouple memcg and objcg stocks"" from Shakeel Butt decouples
   the per-cpu memcg charge cache from the objcg's one.

   This is a step along the way to making memcg and objcg charging
   NMI-safe, which is a BPF requirement.

 - "mm/damon: minor fixups and improvements for code, tests, and
   documents" from SeongJae Park is yet another batch of miscellaneous
   DAMON changes. Fix and improve minor problems in code, tests and
   documents.

 - "memcg: make memcg stats irq safe" from Shakeel Butt converts memcg
   stats to be irq safe. Another step along the way to making memcg
   charging and stats updates NMI-safe, a BPF requirement.

 - "Let unmap_hugepage_range() and several related functions take folio
   instead of page" from Fan Ni provides folio conversions in the
   hugetlb code.

* tag 'mm-stable-2025-05-31-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (285 commits)
  mm: pcp: increase pcp->free_count threshold to trigger free_high
  mm/hugetlb: convert use of struct page to folio in __unmap_hugepage_range()
  mm/hugetlb: refactor __unmap_hugepage_range() to take folio instead of page
  mm/hugetlb: refactor unmap_hugepage_range() to take folio instead of page
  mm/hugetlb: pass folio instead of page to unmap_ref_private()
  memcg: objcg stock trylock without irq disabling
  memcg: no stock lock for cpu hot-unplug
  memcg: make __mod_memcg_lruvec_state re-entrant safe against irqs
  memcg: make count_memcg_events re-entrant safe against irqs
  memcg: make mod_memcg_state re-entrant safe against irqs
  memcg: move preempt disable to callers of memcg_rstat_updated
  memcg: memcg_rstat_updated re-entrant safe against irqs
  mm: khugepaged: decouple SHMEM and file folios' collapse
  selftests/eventfd: correct test name and improve messages
  alloc_tag: check mem_profiling_support in alloc_tag_init
  Docs/damon: update titles and brief introductions to explain DAMOS
  selftests/damon/_damon_sysfs: read tried regions directories in order
  mm/damon/tests/core-kunit: add a test for damos_set_filters_default_reject()
  mm/damon/paddr: remove unused variable, folio_list, in damon_pa_stat()
  mm/damon/sysfs-schemes: fix wrong comment on damons_sysfs_quota_goal_metric_strs
  ...
jfs: implement migrate_folio for jfs_metapage_aops 2025-05-13T06:50:47+00:00 Shivank Garg shivankg@amd.com 2025-04-30T10:01:52+00:00 906d7ce3b59d62cf017ca602a0dfcb29413b8872 Add the missing migrate_folio operation to jfs_metapage_aops to fix warnings during memory compaction. These warnings were introduced by commit 7ee3647243e5 ("migrate: Remove call to ->writepage") which added explicit warnings when filesystems don't implement migrate_folio. System reports following warnings: jfs_metapage_aops does not implement migrate_folio WARNING: CPU: 0 PID: 6870 at mm/migrate.c:955 fallback_migrate_folio mm/migrate.c:953 [inline] WARNING: CPU: 0 PID: 6870 at mm/migrate.c:955 move_to_new_folio+0x70e/0x840 mm/migrate.c:1007 Implement metapage_migrate_folio() which handles both single and multiple metapages per page configurations. [shivankg@amd.com: change comment style] Link: https://lkml.kernel.org/r/1967593d-8084-4a4a-b384-35d5adc54eb4@amd.com [akpm@linux-foundation.org: fix build] [shivankg@amd.com: remove redundant NULL check in __metapage_migrate_folio()] Link: https://lkml.kernel.org/r/a67db238-0ca6-4725-abb2-dc092de87e1b@amd.com Link: https://lkml.kernel.org/r/20250430100150.279751-3-shivankg@amd.com Fixes: 35474d52c605 ("jfs: Convert metapage_writepage to metapage_write_folio") Signed-off-by: Shivank Garg <shivankg@amd.com> Reported-by: syzbot+8bb6fd945af4e0ad9299@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/67faff52.050a0220.379d84.001b.GAE@google.com Tested-by: syzbot+8bb6fd945af4e0ad9299@syzkaller.appspotmail.com Cc: Alistair Popple <apopple@nvidia.com> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Donet Tom <donettom@linux.ibm.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Zi Yan <ziy@nvidia.com> Cc: Dan Carpenter <dan.carpenter@linaro.org> Cc: kernel test robot <lkp@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> 
Add the missing migrate_folio operation to jfs_metapage_aops to fix
warnings during memory compaction.  These warnings were introduced by
commit 7ee3647243e5 ("migrate: Remove call to ->writepage") which added
explicit warnings when filesystems don't implement migrate_folio.

System reports following warnings:
  jfs_metapage_aops does not implement migrate_folio
  WARNING: CPU: 0 PID: 6870 at mm/migrate.c:955 fallback_migrate_folio mm/migrate.c:953 [inline]
  WARNING: CPU: 0 PID: 6870 at mm/migrate.c:955 move_to_new_folio+0x70e/0x840 mm/migrate.c:1007

Implement metapage_migrate_folio() which handles both single and multiple
metapages per page configurations.

[shivankg@amd.com: change comment style]
  Link: https://lkml.kernel.org/r/1967593d-8084-4a4a-b384-35d5adc54eb4@amd.com
[akpm@linux-foundation.org: fix build]
[shivankg@amd.com: remove redundant NULL check in __metapage_migrate_folio()]
  Link: https://lkml.kernel.org/r/a67db238-0ca6-4725-abb2-dc092de87e1b@amd.com
Link: https://lkml.kernel.org/r/20250430100150.279751-3-shivankg@amd.com
Fixes: 35474d52c605 ("jfs: Convert metapage_writepage to metapage_write_folio")
Signed-off-by: Shivank Garg <shivankg@amd.com>
Reported-by: syzbot+8bb6fd945af4e0ad9299@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/67faff52.050a0220.379d84.001b.GAE@google.com
Tested-by: syzbot+8bb6fd945af4e0ad9299@syzkaller.appspotmail.com
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Dave Kleikamp <shaggy@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: kernel test robot <lkp@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
jfs: fix array-index-out-of-bounds read in add_missing_indices 2025-04-03T14:11:43+00:00 Aditya Dutt duttaditya18@gmail.com 2025-04-01T15:29:16+00:00 5dff41a86377563f7a2b968aae00d25b4ceb37c9 stbl is s8 but it must contain offsets into slot which can go from 0 to 127. Added a bound check for that error and return -EIO if the check fails. Also make jfs_readdir return with error if add_missing_indices returns with an error. Reported-by: syzbot+b974bd41515f770c608b@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com./bug?extid=b974bd41515f770c608b Signed-off-by: Aditya Dutt <duttaditya18@gmail.com> Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> 
stbl is s8 but it must contain offsets into slot which can go from 0 to
127.

Added a bound check for that error and return -EIO if the check fails.
Also make jfs_readdir return with error if add_missing_indices returns
with an error.

Reported-by: syzbot+b974bd41515f770c608b@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com./bug?extid=b974bd41515f770c608b
Signed-off-by: Aditya Dutt <duttaditya18@gmail.com>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
jfs: Fix null-ptr-deref in jfs_ioc_trim 2025-04-03T14:11:42+00:00 Dylan Wolff wolffd@comp.nus.edu.sg 2025-03-12T08:02:00+00:00 a4685408ff6c3e2af366ad9a7274f45ff3f394ee [ Syzkaller Report ] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000087: 0000 [#1 KASAN: null-ptr-deref in range [0x0000000000000438-0x000000000000043f] CPU: 2 UID: 0 PID: 10614 Comm: syz-executor.0 Not tainted 6.13.0-rc6-gfbfd64d25c7a-dirty #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Sched_ext: serialise (enabled+all), task: runnable_at=-30ms RIP: 0010:jfs_ioc_trim+0x34b/0x8f0 Code: e7 e8 59 a4 87 fe 4d 8b 24 24 4d 8d bc 24 38 04 00 00 48 8d 93 90 82 fe ff 4c 89 ff 31 f6 RSP: 0018:ffffc900055f7cd0 EFLAGS: 00010206 RAX: 0000000000000087 RBX: 00005866a9e67ff8 RCX: 000000000000000a RDX: 0000000000000001 RSI: 0000000000000004 RDI: 0000000000000001 RBP: dffffc0000000000 R08: ffff88807c180003 R09: 1ffff1100f830000 R10: dffffc0000000000 R11: ffffed100f830001 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000438 FS: 00007fe520225640(0000) GS:ffff8880b7e80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005593c91b2c88 CR3: 000000014927c000 CR4: 00000000000006f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> ? __die_body+0x61/0xb0 ? die_addr+0xb1/0xe0 ? exc_general_protection+0x333/0x510 ? asm_exc_general_protection+0x26/0x30 ? jfs_ioc_trim+0x34b/0x8f0 jfs_ioctl+0x3c8/0x4f0 ? __pfx_jfs_ioctl+0x10/0x10 ? __pfx_jfs_ioctl+0x10/0x10 __se_sys_ioctl+0x269/0x350 ? __pfx___se_sys_ioctl+0x10/0x10 ? do_syscall_64+0xfb/0x210 do_syscall_64+0xee/0x210 ? syscall_exit_to_user_mode+0x1e0/0x330 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe51f4903ad Code: c3 e8 a7 2b 00 00 0f 1f 80 00 00 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d RSP: 002b:00007fe5202250c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fe51f5cbf80 RCX: 00007fe51f4903ad RDX: 0000000020000680 RSI: 00000000c0185879 RDI: 0000000000000005 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe520225640 R13: 000000000000000e R14: 00007fe51f44fca0 R15: 00007fe52021d000 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:jfs_ioc_trim+0x34b/0x8f0 Code: e7 e8 59 a4 87 fe 4d 8b 24 24 4d 8d bc 24 38 04 00 00 48 8d 93 90 82 fe ff 4c 89 ff 31 f6 RSP: 0018:ffffc900055f7cd0 EFLAGS: 00010206 RAX: 0000000000000087 RBX: 00005866a9e67ff8 RCX: 000000000000000a RDX: 0000000000000001 RSI: 0000000000000004 RDI: 0000000000000001 RBP: dffffc0000000000 R08: ffff88807c180003 R09: 1ffff1100f830000 R10: dffffc0000000000 R11: ffffed100f830001 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000438 FS: 00007fe520225640(0000) GS:ffff8880b7e80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005593c91b2c88 CR3: 000000014927c000 CR4: 00000000000006f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Kernel panic - not syncing: Fatal exception [ Analysis ] We believe that we have found a concurrency bug in the `fs/jfs` module that results in a null pointer dereference. There is a closely related issue which has been fixed: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d6c1b3599b2feb5c7291f5ac3a36e5fa7cedb234 ... but, unfortunately, the accepted patch appears to still be susceptible to a null pointer dereference under some interleavings. To trigger the bug, we think that `JFS_SBI(ipbmap->i_sb)->bmap` is set to NULL in `dbFreeBits` and then dereferenced in `jfs_ioc_trim`. This bug manifests quite rarely under normal circumstances, but is triggereable from a syz-program. Reported-and-tested-by: Dylan J. Wolff<wolffd@comp.nus.edu.sg> Reported-and-tested-by: Jiacheng Xu <stitch@zju.edu.cn> Signed-off-by: Dylan J. Wolff<wolffd@comp.nus.edu.sg> Signed-off-by: Jiacheng Xu <stitch@zju.edu.cn> Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> 
[ Syzkaller Report ]

Oops: general protection fault, probably for non-canonical address
0xdffffc0000000087: 0000 [#1
KASAN: null-ptr-deref in range [0x0000000000000438-0x000000000000043f]
CPU: 2 UID: 0 PID: 10614 Comm: syz-executor.0 Not tainted
6.13.0-rc6-gfbfd64d25c7a-dirty #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
Sched_ext: serialise (enabled+all), task: runnable_at=-30ms
RIP: 0010:jfs_ioc_trim+0x34b/0x8f0
Code: e7 e8 59 a4 87 fe 4d 8b 24 24 4d 8d bc 24 38 04 00 00 48 8d 93
90 82 fe ff 4c 89 ff 31 f6
RSP: 0018:ffffc900055f7cd0 EFLAGS: 00010206
RAX: 0000000000000087 RBX: 00005866a9e67ff8 RCX: 000000000000000a
RDX: 0000000000000001 RSI: 0000000000000004 RDI: 0000000000000001
RBP: dffffc0000000000 R08: ffff88807c180003 R09: 1ffff1100f830000
R10: dffffc0000000000 R11: ffffed100f830001 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000438
FS:  00007fe520225640(0000) GS:ffff8880b7e80000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005593c91b2c88 CR3: 000000014927c000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
? __die_body+0x61/0xb0
? die_addr+0xb1/0xe0
? exc_general_protection+0x333/0x510
? asm_exc_general_protection+0x26/0x30
? jfs_ioc_trim+0x34b/0x8f0
jfs_ioctl+0x3c8/0x4f0
? __pfx_jfs_ioctl+0x10/0x10
? __pfx_jfs_ioctl+0x10/0x10
__se_sys_ioctl+0x269/0x350
? __pfx___se_sys_ioctl+0x10/0x10
? do_syscall_64+0xfb/0x210
do_syscall_64+0xee/0x210
? syscall_exit_to_user_mode+0x1e0/0x330
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe51f4903ad
Code: c3 e8 a7 2b 00 00 0f 1f 80 00 00 00 00 f3 0f 1e fa 48 89 f8 48
89 f7 48 89 d6 48 89 ca 4d
RSP: 002b:00007fe5202250c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fe51f5cbf80 RCX: 00007fe51f4903ad
RDX: 0000000020000680 RSI: 00000000c0185879 RDI: 0000000000000005
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe520225640
R13: 000000000000000e R14: 00007fe51f44fca0 R15: 00007fe52021d000
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:jfs_ioc_trim+0x34b/0x8f0
Code: e7 e8 59 a4 87 fe 4d 8b 24 24 4d 8d bc 24 38 04 00 00 48 8d 93
90 82 fe ff 4c 89 ff 31 f6
RSP: 0018:ffffc900055f7cd0 EFLAGS: 00010206
RAX: 0000000000000087 RBX: 00005866a9e67ff8 RCX: 000000000000000a
RDX: 0000000000000001 RSI: 0000000000000004 RDI: 0000000000000001
RBP: dffffc0000000000 R08: ffff88807c180003 R09: 1ffff1100f830000
R10: dffffc0000000000 R11: ffffed100f830001 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000438
FS:  00007fe520225640(0000) GS:ffff8880b7e80000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005593c91b2c88 CR3: 000000014927c000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Kernel panic - not syncing: Fatal exception

[ Analysis ]

We believe that we have found a concurrency bug in the `fs/jfs` module
that results in a null pointer dereference. There is a closely related
issue which has been fixed:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d6c1b3599b2feb5c7291f5ac3a36e5fa7cedb234

... but, unfortunately, the accepted patch appears to still be
susceptible to a null pointer dereference under some interleavings.

To trigger the bug, we think that `JFS_SBI(ipbmap->i_sb)->bmap` is set
to NULL in `dbFreeBits` and then dereferenced in `jfs_ioc_trim`. This
bug manifests quite rarely under normal circumstances, but is
triggereable from a syz-program.

Reported-and-tested-by: Dylan J. Wolff<wolffd@comp.nus.edu.sg>
Reported-and-tested-by: Jiacheng Xu <stitch@zju.edu.cn>
Signed-off-by: Dylan J. Wolff<wolffd@comp.nus.edu.sg>
Signed-off-by: Jiacheng Xu <stitch@zju.edu.cn>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
jfs: validate AG parameters in dbMount() to prevent crashes 2025-04-03T14:11:42+00:00 Vasiliy Kovalev kovalev@altlinux.org 2025-03-10T08:56:02+00:00 37bfb464ddca87f203071b5bd562cd91ddc0b40a Validate db_agheight, db_agwidth, and db_agstart in dbMount to catch corrupted metadata early and avoid undefined behavior in dbAllocAG. Limits are derived from L2LPERCTL, LPERCTL/MAXAG, and CTLTREESIZE: - agheight: 0 to L2LPERCTL/2 (0 to 5) ensures shift (L2LPERCTL - 2*agheight) >= 0. - agwidth: 1 to min(LPERCTL/MAXAG, 2^(L2LPERCTL - 2*agheight)) ensures agperlev >= 1. - Ranges: 1-8 (agheight 0-3), 1-4 (agheight 4), 1 (agheight 5). - LPERCTL/MAXAG = 1024/128 = 8 limits leaves per AG; 2^(10 - 2*agheight) prevents division to 0. - agstart: 0 to CTLTREESIZE-1 - agwidth*(MAXAG-1) keeps ti within stree (size 1365). - Ranges: 0-1237 (agwidth 1), 0-348 (agwidth 8). UBSAN: shift-out-of-bounds in fs/jfs/jfs_dmap.c:1400:9 shift exponent -335544310 is negative CPU: 0 UID: 0 PID: 5822 Comm: syz-executor130 Not tainted 6.14.0-rc5-syzkaller #0 Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 ubsan_epilogue lib/ubsan.c:231 [inline] __ubsan_handle_shift_out_of_bounds+0x3c8/0x420 lib/ubsan.c:468 dbAllocAG+0x1087/0x10b0 fs/jfs/jfs_dmap.c:1400 dbDiscardAG+0x352/0xa20 fs/jfs/jfs_dmap.c:1613 jfs_ioc_trim+0x45a/0x6b0 fs/jfs/jfs_discard.c:105 jfs_ioctl+0x2cd/0x3e0 fs/jfs/ioctl.c:131 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Found by Linux Verification Center (linuxtesting.org) with Syzkaller. Cc: stable@vger.kernel.org Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot+fe8264911355151c487f@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=fe8264911355151c487f Signed-off-by: Vasiliy Kovalev <kovalev@altlinux.org> Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> 
Validate db_agheight, db_agwidth, and db_agstart in dbMount to catch
corrupted metadata early and avoid undefined behavior in dbAllocAG.
Limits are derived from L2LPERCTL, LPERCTL/MAXAG, and CTLTREESIZE:

- agheight: 0 to L2LPERCTL/2 (0 to 5) ensures shift
  (L2LPERCTL - 2*agheight) >= 0.
- agwidth: 1 to min(LPERCTL/MAXAG, 2^(L2LPERCTL - 2*agheight))
  ensures agperlev >= 1.
  - Ranges: 1-8 (agheight 0-3), 1-4 (agheight 4), 1 (agheight 5).
  - LPERCTL/MAXAG = 1024/128 = 8 limits leaves per AG;
    2^(10 - 2*agheight) prevents division to 0.
- agstart: 0 to CTLTREESIZE-1 - agwidth*(MAXAG-1) keeps ti within
  stree (size 1365).
  - Ranges: 0-1237 (agwidth 1), 0-348 (agwidth 8).

UBSAN: shift-out-of-bounds in fs/jfs/jfs_dmap.c:1400:9
shift exponent -335544310 is negative
CPU: 0 UID: 0 PID: 5822 Comm: syz-executor130 Not tainted 6.14.0-rc5-syzkaller #0
Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 ubsan_epilogue lib/ubsan.c:231 [inline]
 __ubsan_handle_shift_out_of_bounds+0x3c8/0x420 lib/ubsan.c:468
 dbAllocAG+0x1087/0x10b0 fs/jfs/jfs_dmap.c:1400
 dbDiscardAG+0x352/0xa20 fs/jfs/jfs_dmap.c:1613
 jfs_ioc_trim+0x45a/0x6b0 fs/jfs/jfs_discard.c:105
 jfs_ioctl+0x2cd/0x3e0 fs/jfs/ioctl.c:131
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Cc: stable@vger.kernel.org
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: syzbot+fe8264911355151c487f@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=fe8264911355151c487f
Signed-off-by: Vasiliy Kovalev <kovalev@altlinux.org>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Merge tag 'jfs-6.14' of github.com:kleikamp/linux-shaggy 2025-03-27T20:17:39+00:00 Linus Torvalds torvalds@linux-foundation.org 2025-03-27T20:17:39+00:00 f79adee883586b94cf977e4d28384ea0288473ed Pull jfs updates from David Kleikamp: "Various bug fixes and cleanups for JFS" * tag 'jfs-6.14' of github.com:kleikamp/linux-shaggy: jfs: add index corruption check to DT_GETPAGE() fs/jfs: consolidate sanity checking in dbMount jfs: add sanity check for agwidth in dbMount jfs: Prevent copying of nlink with value 0 from disk inode fs/jfs: Prevent integer overflow in AG size calculation fs/jfs: cast inactags to s64 to prevent potential overflow jfs: Fix uninit-value access of imap allocated in the diMount() function jfs: fix slab-out-of-bounds read in ea_get() jfs: add check read-only before truncation in jfs_truncate_nolock() jfs: add check read-only before txBeginAnon() call jfs: reject on-disk inodes of an unsupported type jfs: Remove reference to bh->b_page jfs: Delete a couple tabs in jfs_reconfigure() 
Pull jfs updates from David Kleikamp:
 "Various bug fixes and cleanups for JFS"

* tag 'jfs-6.14' of github.com:kleikamp/linux-shaggy:
  jfs: add index corruption check to DT_GETPAGE()
  fs/jfs: consolidate sanity checking in dbMount
  jfs: add sanity check for agwidth in dbMount
  jfs: Prevent copying of nlink with value 0 from disk inode
  fs/jfs: Prevent integer overflow in AG size calculation
  fs/jfs: cast inactags to s64 to prevent potential overflow
  jfs: Fix uninit-value access of imap allocated in the diMount() function
  jfs: fix slab-out-of-bounds read in ea_get()
  jfs: add check read-only before truncation in jfs_truncate_nolock()
  jfs: add check read-only before txBeginAnon() call
  jfs: reject on-disk inodes of an unsupported type
  jfs: Remove reference to bh->b_page
  jfs: Delete a couple tabs in jfs_reconfigure()
jfs: add index corruption check to DT_GETPAGE() 2025-03-11T16:53:40+00:00 Roman Smirnov r.smirnov@omp.ru 2025-02-26T08:25:22+00:00 a8dfb2168906944ea61acfc87846b816eeab882d If the file system is corrupted, the header.stblindex variable may become greater than 127. Because of this, an array access out of bounds may occur: ------------[ cut here ]------------ UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dtree.c:3096:10 index 237 is out of range for type 'struct dtslot[128]' CPU: 0 UID: 0 PID: 5822 Comm: syz-executor740 Not tainted 6.13.0-rc4-syzkaller-00110-g4099a71718b0 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 ubsan_epilogue lib/ubsan.c:231 [inline] __ubsan_handle_out_of_bounds+0x121/0x150 lib/ubsan.c:429 dtReadFirst+0x622/0xc50 fs/jfs/jfs_dtree.c:3096 dtReadNext fs/jfs/jfs_dtree.c:3147 [inline] jfs_readdir+0x9aa/0x3c50 fs/jfs/jfs_dtree.c:2862 wrap_directory_iterator+0x91/0xd0 fs/readdir.c:65 iterate_dir+0x571/0x800 fs/readdir.c:108 __do_sys_getdents64 fs/readdir.c:403 [inline] __se_sys_getdents64+0x1e2/0x4b0 fs/readdir.c:389 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f </TASK> ---[ end trace ]--- Add a stblindex check for corruption. Reported-by: syzbot <syzbot+9120834fc227768625ba@syzkaller.appspotmail.com> Closes: https://syzkaller.appspot.com/bug?extid=9120834fc227768625ba Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Roman Smirnov <r.smirnov@omp.ru> Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> 
If the file system is corrupted, the header.stblindex variable
may become greater than 127. Because of this, an array access out
of bounds may occur:

------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dtree.c:3096:10
index 237 is out of range for type 'struct dtslot[128]'
CPU: 0 UID: 0 PID: 5822 Comm: syz-executor740 Not tainted 6.13.0-rc4-syzkaller-00110-g4099a71718b0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 ubsan_epilogue lib/ubsan.c:231 [inline]
 __ubsan_handle_out_of_bounds+0x121/0x150 lib/ubsan.c:429
 dtReadFirst+0x622/0xc50 fs/jfs/jfs_dtree.c:3096
 dtReadNext fs/jfs/jfs_dtree.c:3147 [inline]
 jfs_readdir+0x9aa/0x3c50 fs/jfs/jfs_dtree.c:2862
 wrap_directory_iterator+0x91/0xd0 fs/readdir.c:65
 iterate_dir+0x571/0x800 fs/readdir.c:108
 __do_sys_getdents64 fs/readdir.c:403 [inline]
 __se_sys_getdents64+0x1e2/0x4b0 fs/readdir.c:389
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
 </TASK>
---[ end trace ]---

Add a stblindex check for corruption.

Reported-by: syzbot <syzbot+9120834fc227768625ba@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=9120834fc227768625ba
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Roman Smirnov <r.smirnov@omp.ru>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Change inode_operations.mkdir to return struct dentry * 2025-02-27T19:00:17+00:00 NeilBrown neilb@suse.de 2025-02-27T01:32:53+00:00 88d5baf69082e5b410296435008329676b687549 Some filesystems, such as NFS, cifs, ceph, and fuse, do not have complete control of sequencing on the actual filesystem (e.g. on a different server) and may find that the inode created for a mkdir request already exists in the icache and dcache by the time the mkdir request returns. For example, if the filesystem is mounted twice the directory could be visible on the other mount before it is on the original mount, and a pair of name_to_handle_at(), open_by_handle_at() calls could instantiate the directory inode with an IS_ROOT() dentry before the first mkdir returns. This means that the dentry passed to ->mkdir() may not be the one that is associated with the inode after the ->mkdir() completes. Some callers need to interact with the inode after the ->mkdir completes and they currently need to perform a lookup in the (rare) case that the dentry is no longer hashed. This lookup-after-mkdir requires that the directory remains locked to avoid races. Planned future patches to lock the dentry rather than the directory will mean that this lookup cannot be performed atomically with the mkdir. To remove this barrier, this patch changes ->mkdir to return the resulting dentry if it is different from the one passed in. Possible returns are: NULL - the directory was created and no other dentry was used ERR_PTR() - an error occurred non-NULL - this other dentry was spliced in This patch only changes file-systems to return "ERR_PTR(err)" instead of "err" or equivalent transformations. Subsequent patches will make further changes to some file-systems to return a correct dentry. Not all filesystems reliably result in a positive hashed dentry: - NFS, cifs, hostfs will sometimes need to perform a lookup of the name to get inode information. Races could result in this returning something different. Note that this lookup is non-atomic which is what we are trying to avoid. Placing the lookup in filesystem code means it only happens when the filesystem has no other option. - kernfs and tracefs leave the dentry negative and the ->revalidate operation ensures that lookup will be called to correctly populate the dentry. This could be fixed but I don't think it is important to any of the users of vfs_mkdir() which look at the dentry. The recommendation to use d_drop();d_splice_alias() is ugly but fits with current practice. A planned future patch will change this. Reviewed-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: NeilBrown <neilb@suse.de> Link: https://lore.kernel.org/r/20250227013949.536172-2-neilb@suse.de Signed-off-by: Christian Brauner <brauner@kernel.org> 
Some filesystems, such as NFS, cifs, ceph, and fuse, do not have
complete control of sequencing on the actual filesystem (e.g.  on a
different server) and may find that the inode created for a mkdir
request already exists in the icache and dcache by the time the mkdir
request returns.  For example, if the filesystem is mounted twice the
directory could be visible on the other mount before it is on the
original mount, and a pair of name_to_handle_at(), open_by_handle_at()
calls could instantiate the directory inode with an IS_ROOT() dentry
before the first mkdir returns.

This means that the dentry passed to ->mkdir() may not be the one that
is associated with the inode after the ->mkdir() completes.  Some
callers need to interact with the inode after the ->mkdir completes and
they currently need to perform a lookup in the (rare) case that the
dentry is no longer hashed.

This lookup-after-mkdir requires that the directory remains locked to
avoid races.  Planned future patches to lock the dentry rather than the
directory will mean that this lookup cannot be performed atomically with
the mkdir.

To remove this barrier, this patch changes ->mkdir to return the
resulting dentry if it is different from the one passed in.
Possible returns are:
  NULL - the directory was created and no other dentry was used
  ERR_PTR() - an error occurred
  non-NULL - this other dentry was spliced in

This patch only changes file-systems to return "ERR_PTR(err)" instead of
"err" or equivalent transformations.  Subsequent patches will make
further changes to some file-systems to return a correct dentry.

Not all filesystems reliably result in a positive hashed dentry:

- NFS, cifs, hostfs will sometimes need to perform a lookup of
  the name to get inode information.  Races could result in this
  returning something different. Note that this lookup is
  non-atomic which is what we are trying to avoid.  Placing the
  lookup in filesystem code means it only happens when the filesystem
  has no other option.
- kernfs and tracefs leave the dentry negative and the ->revalidate
  operation ensures that lookup will be called to correctly populate
  the dentry.  This could be fixed but I don't think it is important
  to any of the users of vfs_mkdir() which look at the dentry.

The recommendation to use
    d_drop();d_splice_alias()
is ugly but fits with current practice.  A planned future patch will
change this.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: NeilBrown <neilb@suse.de>
Link: https://lore.kernel.org/r/20250227013949.536172-2-neilb@suse.de
Signed-off-by: Christian Brauner <brauner@kernel.org>
fs/jfs: consolidate sanity checking in dbMount 2025-02-20T16:31:19+00:00 Dave Kleikamp dave.kleikamp@oracle.com 2025-02-20T16:31:19+00:00 0d250b1c52484d489e31df2cf9118b7c4bd49d31 Sanity checks have been added to dbMount as individual if clauses with identical error handling. Move these all into one clause. Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> 
Sanity checks have been added to dbMount as individual if clauses with
identical error handling. Move these all into one clause.

Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
jfs: add sanity check for agwidth in dbMount 2025-02-20T16:19:46+00:00 Edward Adam Davis eadavis@qq.com 2025-02-20T11:24:19+00:00 ddf2846f22e8575d6b4b6a66f2100f168b8cd73d The width in dmapctl of the AG is zero, it trigger a divide error when calculating the control page level in dbAllocAG. To avoid this issue, add a check for agwidth in dbAllocAG. Reported-and-tested-by: syzbot+7c808908291a569281a9@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=7c808908291a569281a9 Signed-off-by: Edward Adam Davis <eadavis@qq.com> Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> 
The width in dmapctl of the AG is zero, it trigger a divide error when
calculating the control page level in dbAllocAG.

To avoid this issue, add a check for agwidth in dbAllocAG.

Reported-and-tested-by: syzbot+7c808908291a569281a9@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=7c808908291a569281a9
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>