kernel/linux.git/Documentation, branch v6.18.37

crypto: qat - remove unused character device and IOCTLs

2026-06-27T10:06:49+00:00

commit d237230728c567297f2f98b425d63156ab2ed17f upstream. The QAT driver exposes a character device (qat_adf_ctl) with IOCTLs for device configuration, start, stop, status query and enumeration. These IOCTLs are not part of any public uAPI header and have no known in-tree or out-of-tree users. Device lifecycle is already managed via sysfs. The ioctl interface also increases the attack surface and is the subject of a number of bug reports. Remove the character device, the IOCTL definitions, and the related data structures (adf_dev_status_info, adf_user_cfg_key_val, adf_user_cfg_section, adf_user_cfg_ctl_data). Drop the now-unused adf_cfg_user.h header and strip adf_ctl_drv.c down to the minimal module_init/module_exit hooks for workqueue, AER, and crypto/compression algorithm registration. Clean up leftover dead code that was only reachable from the removed IOCTL paths: adf_cfg_del_all(), adf_devmgr_verify_id(), adf_devmgr_get_num_dev(), adf_devmgr_get_dev_by_id(), adf_get_vf_real_id() and the unused ADF_CFG macros. Additionally, drop the entry associated to QAT IOCTLs in ioctl-number.rst. Cc: stable@vger.kernel.org Fixes: d8cba25d2c68 ("crypto: qat - Intel(R) QAT driver framework") Reported-by: Zhi Wang Reported-by: Bin Yu Reported-by: MingYu Wang Closes: https://lore.kernel.org/all/61d6d499.ab89.19b9b7f3186.Coremail.wangzhi_xd@stu.xidian.edu.cn/ Link: https://lore.kernel.org/all/20260508034841.256794-1-w15303746062@163.com/ Link: https://lore.kernel.org/all/20260508023542.256299-1-w15303746062@163.com/ Link: https://lore.kernel.org/all/20260504025120.98242-1-w15303746062@163.com/ Signed-off-by: Giovanni Cabiddu Reviewed-by: Ahsan Atta Signed-off-by: Herbert Xu Signed-off-by: Greg Kroah-Hartman

mm: introduce VM_MAYBE_GUARD and make visible in /proc/$pid/smaps

2026-06-27T10:06:48+00:00

commit 5dba5cc2e0ffa76f2f6c8922a04469dc9602c396 upstream. Patch series "introduce VM_MAYBE_GUARD and make it sticky", v4. Currently, guard regions are not visible to users except through /proc/$pid/pagemap, with no explicit visibility at the VMA level. This makes the feature less useful, as it isn't entirely apparent which VMAs may have these entries present, especially when performing actions which walk through memory regions such as those performed by CRIU. This series addresses this issue by introducing the VM_MAYBE_GUARD flag which fulfils this role, updating the smaps logic to display an entry for these. The semantics of this flag are that a guard region MAY be present if set (we cannot be sure, as we can't efficiently track whether an MADV_GUARD_REMOVE finally removes all the guard regions in a VMA) - but if not set the VMA definitely does NOT have any guard regions present. It's problematic to establish this flag without further action, because that means that VMAs with guard regions in them become non-mergeable with adjacent VMAs for no especially good reason. To work around this, this series also introduces the concept of 'sticky' VMA flags - that is flags which: a. if set in one VMA and not in another still permit those VMAs to be merged (if otherwise compatible). b. When they are merged, the resultant VMA must have the flag set. The VMA logic is updated to propagate these flags correctly. Additionally, VM_MAYBE_GUARD being an explicit VMA flag allows us to solve an issue with file-backed guard regions - previously these established an anon_vma object for file-backed mappings solely to have vma_needs_copy() correctly propagate guard region mappings to child processes. We introduce a new flag alias VM_COPY_ON_FORK (which currently only specifies VM_MAYBE_GUARD) and update vma_needs_copy() to check explicitly for this flag and to copy page tables if it is present, which resolves this issue. Additionally, we add the ability for allow-listed VMA flags to be atomically writable with only mmap/VMA read locks held. The only flag we allow so far is VM_MAYBE_GUARD, which we carefully ensure does not cause any races by being allowed to do so. This allows us to maintain guard region installation as a read-locked operation and not endure the overhead of obtaining a write lock here. Finally we introduce extensive VMA userland tests to assert that the sticky VMA logic behaves correctly as well as guard region self tests to assert that smaps visibility is correctly implemented. This patch (of 9): Currently, if a user needs to determine if guard regions are present in a range, they have to scan all VMAs (or have knowledge of which ones might have guard regions). Since commit 8e2f2aeb8b48 ("fs/proc/task_mmu: add guard region bit to pagemap") and the related commit a516403787e0 ("fs/proc: extend the PAGEMAP_SCAN ioctl to report guard regions"), users can use either /proc/$pid/pagemap or the PAGEMAP_SCAN functionality to perform this operation at a virtual address level. This is not ideal, and it gives no visibility at a /proc/$pid/smaps level that guard regions exist in ranges. This patch remedies the situation by establishing a new VMA flag, VM_MAYBE_GUARD, to indicate that a VMA may contain guard regions (it is uncertain because we cannot reasonably determine whether a MADV_GUARD_REMOVE call has removed all of the guard regions in a VMA, and additionally VMAs may change across merge/split). We utilise 0x800 for this flag which makes it available to 32-bit architectures also, a flag that was previously used by VM_DENYWRITE, which was removed in commit 8d0920bde5eb ("mm: remove VM_DENYWRITE") and hasn't bee reused yet. We also update the smaps logic and documentation to identify these VMAs. Another major use of this functionality is that we can use it to identify that we ought to copy page tables on fork. We do not actually implement usage of this flag in mm/madvise.c yet as we need to allow some VMA flags to be applied atomically under mmap/VMA read lock in order to avoid the need to acquire a write lock for this purpose. Link: https://lkml.kernel.org/r/cover.1763460113.git.ljs@kernel.org Link: https://lkml.kernel.org/r/cf8ef821eba29b6c5b5e138fffe95d6dcabdedb9.1763460113.git.ljs@kernel.org Signed-off-by: Lorenzo Stoakes Reviewed-by: Pedro Falcato Reviewed-by: Vlastimil Babka Acked-by: David Hildenbrand (Red Hat) Reviewed-by: Lance Yang Cc: Andrei Vagin Cc: Baolin Wang Cc: Barry Song Cc: Dev Jain Cc: Jann Horn Cc: Jonathan Corbet Cc: Liam Howlett Cc: "Masami Hiramatsu (Google)" Cc: Mathieu Desnoyers Cc: Michal Hocko Cc: Mike Rapoport Cc: Nico Pache Cc: Ryan Roberts Cc: Steven Rostedt Cc: Suren Baghdasaryan Cc: Zi Yan Signed-off-by: Andrew Morton Signed-off-by: Ahmed Elaidy Signed-off-by: Greg Kroah-Hartman

arm64: errata: Mitigate TLBI errata on Microsoft Azure Cobalt 100 CPU

2026-06-19T11:44:16+00:00

commit 1940e70a8144bf75e6df26bf6f600862ea7f7ea1 upstream. Commit fb091ff39479 ("arm64: Subscribe Microsoft Azure Cobalt 100 to ARM Neoverse N2 errata") states that Microsoft Azure Cobalt 100 CPU "is a Microsoft implemented CPU based on r0p0 of the ARM Neoverse N2 CPU, and therefore suffers from all the same errata.". So enable the workaround for the latest broadcast TLB invalidation bug on these parts. Signed-off-by: Will Deacon [Mark: backport to v6.18.y] Signed-off-by: Mark Rutland Signed-off-by: Greg Kroah-Hartman

arm64: errata: Mitigate TLBI errata on NVIDIA Olympus CPU

2026-06-19T11:44:16+00:00

commit ec7216f92e4ebd485b1c6dc6aa3f6064b71a5768 upstream. NVIDIA Olympus cores are affected by the TLBI completion issue tracked as CVE-2025-10263. The existing ARM64_ERRATUM_4118414 handling already uses ARM64_WORKAROUND_REPEAT_TLBI to issue an additional broadcast TLBI;DSB sequence and ensure affected memory write effects are globally observed. Add MIDR_NVIDIA_OLYMPUS to the repeat-TLBI match list so the same mitigation is enabled on affected Olympus systems. Also document the NVIDIA Olympus erratum in the arm64 silicon errata table and list it in the Kconfig help text. Signed-off-by: Shanker Donthineni Cc: Catalin Marinas Cc: Will Deacon Cc: Mark Rutland Acked-by: Mark Rutland Signed-off-by: Will Deacon [Mark: backport to v6.18.y] Signed-off-by: Shanker Donthineni Signed-off-by: Greg Kroah-Hartman

arm64: errata: Mitigate TLBI errata on various Arm CPUs

2026-06-19T11:44:16+00:00

commit cfd391e74134db664feb499d43af286380b10ba8 upstream. A number of CPUs developed by Arm suffer from errata whereby a broadcast TLBI;DSB sequence may complete before the global observation of writes which are translated by an affected TLB entry. These errata ONLY affect the completion of memory accesses which have been translated by an invalidated TLB entry, and these errata DO NOT affect the actual invalidation of TLB entries. TLB entries are removed correctly. This issue has been assigned CVE ID CVE-2025-10263. To mitigate this issue, Arm recommends that software follows any affected TLBI;DSB sequence with an additional TLBI;DSB, which will ensure that all memory write effects affected by the first TLBI have been globally observed. The additional TLBI can use any operation that is broadcast to affected CPUs, and the additional DSB can use any option that is sufficient to complete the additional TLBI. The ARM64_WORKAROUND_REPEAT_TLBI workaround is sufficient to mitigate the issue. Enable this workaround for affected CPUs, and update the silicon errata documentation accordingly. Note that due to the manner in which Arm develops IP and tracks errata, some CPUs share a common erratum number. Signed-off-by: Mark Rutland Cc: Catalin Marinas Cc: Will Deacon Signed-off-by: Will Deacon [Mark: backport to v6.18.y] Signed-off-by: Mark Rutland Signed-off-by: Greg Kroah-Hartman

erofs: tidy up synchronous decompression

2026-06-19T11:43:51+00:00

[ Upstream commit cc831ab33644088c1eef78936de24701014d520a ] - Get rid of `sbi->opt.max_sync_decompress_pages` since it's fixed as 3 all the time; - Add Z_EROFS_MAX_SYNC_DECOMPRESS_BYTES in bytes instead of in pages, since for non-4K pages, 3-page limitation makes no sense; - Move `sync_decompress` to sbi to avoid unexpected remount impact; - Fold z_erofs_is_sync_decompress() into its caller; - Better description of sysfs entry `sync_decompress`. Reviewed-by: Chao Yu Signed-off-by: Gao Xiang Stable-dep-of: 1aee05e814d2 ("erofs: fix use-after-free on sbi->sync_decompress") Signed-off-by: Sasha Levin

tools: ynl: add scope qualifier for definitions

2026-06-09T10:28:53+00:00

commit fbf5df34a4dbcd09d433dd4f0916bf9b2ddb16de upstream. Using definitions in kernel policies is awkward right now. On one hand we want defines for max values and such. On the other we don't have a way of adding kernel-only defines. Adding unnecessary defines to uAPI is a bad idea, we won't be able to delete them. And when it comes to policy user space should just query it via the policy dump, not use hard coded defines. Add a "scope" property to definitions, which will let us tell the codegen that a definition is for kernel use only. Support following values: - uapi: render into the uAPI header (default, today's behavior) - kernel: render to kernel header only - user: same as kernel but for the user-side generated header Definitions may have a header property (definition is "external", provided by existing header). Extend the scope to headers, too. If definition has both scope and header properties we will only generate the includes in the right scope. Signed-off-by: Jakub Kicinski Link: https://patch.msgid.link/20260510192904.3987113-8-kuba@kernel.org Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman

net/handshake: Pass negative errno through handshake_complete()

2026-06-09T10:28:30+00:00

[ Upstream commit 6b22d433aa13f68e3cd9534ca9a5f4277bfa01c2 ] handshake_complete() declares status as unsigned int and tls_handshake_done() negates that value (-status) before handing it to the TLS consumer. Consumers match on negative errno constants -- xs_tls_handshake_done() has switch (status) { case 0: case -EACCES: case -ETIMEDOUT: lower_transport->xprt_err = status; break; default: lower_transport->xprt_err = -EACCES; } so the API as designed expects callers to pass positive errno values that the tlshd shim then negates. Three internal callers in handshake_nl_accept_doit(), the net-exit drain, and a kunit test follow kernel convention and pass negative errnos -- -EIO, -ETIMEDOUT, -ETIMEDOUT. The implicit conversion to unsigned int turns -ETIMEDOUT into 0xFFFFFF92; the subsequent -status in tls_handshake_done() wraps back to 110, the consumer's switch falls through, and the xprt reports -EACCES on what should be -ETIMEDOUT or -EIO. Fix the API rather than the call sites. The natural kernel convention is negative errno in, negative errno out. Change handshake_complete() and hp_done to take int status, drop the negation in tls_handshake_done(), and negate once in handshake_nl_done_doit() where status arrives from the wire as an unsigned netlink attribute. The three internal callers were already correct under that convention and need no change. At the same wire boundary, declare MAX_ERRNO as the netlink policy upper bound for HANDSHAKE_A_DONE_STATUS. Attribute validation rejects out-of-range values before handshake_nl_done_doit() runs, and negating a bounded u32 there stays within int range -- closing the UBSAN-visible signed- integer overflow that an unconstrained u32 would invoke. Fixes: 3b3009ea8abb ("net/handshake: Create a NETLINK service for handling handshake requests") Signed-off-by: Chuck Lever Reviewed-by: Hannes Reinecke Link: https://patch.msgid.link/20260525-handshake-file-pin-v3-3-66c616906ead@oracle.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

crypto/krb5, rxrpc: Fix lack of pre-decrypt/pre-verify length checks

2026-06-01T15:51:06+00:00

[ Upstream commit 2b50aceafe6606ea52ed42aadd1b4d44a188aade ] Change the krb5 crypto library to provide facilities to precheck the length of the message about to be decrypted or verified. Fix AF_RXRPC to make use of this to validate DATA packets secured with RxGK. Fixes: 9d1d2b59341f ("rxrpc: rxgk: Implement the yfs-rxgk security class (GSSAPI)") Closes: https://sashiko.dev/#/patchset/20260511160753.607296-1-dhowells%40redhat.com Signed-off-by: David Howells cc: Herbert Xu cc: Simon Horman cc: Chuck Lever cc: linux-afs@lists.infradead.org Reviewed-by: Jeffrey Altman Tested-by: Marc Dionne Link: https://patch.msgid.link/20260515230516.2718212-2-dhowells@redhat.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

Documentation: intel_pstate: Fix description of asymmetric packing with SMT

2026-06-01T15:50:59+00:00

[ Upstream commit ee047fc7a2da90554410128195058c409a391d43 ] Patchset [1], including commits 046a5a95c3b0 ("x86/sched/itmt: Give all SMT siblings of a core the same priority") 995998ebdebd ("x86/sched: Remove SD_ASYM_PACKING from the SMT domain flags") overhauled asym_packing handling in the scheduler on x86 hybrid processors with SMT. It removed SD_ASYM_PACKING from the x86 SMT scheduling domain and made all SMT siblings of a core share the same priority. As a result, asym_packing operates only across physical cores, spreading tasks among them and only using idle SMT siblings once all physical cores are busy. Fix the documentation to reflect this behavior. Fixes: f20af84c29b2 ("cpufreq: intel_pstate: Document hybrid processor support") Link: https://lore.kernel.org/r/20230406203148.19182-1-ricardo.neri-calderon@linux.intel.com [1] Signed-off-by: Ricardo Neri [ rjw: Changelog edits ] Link: https://patch.msgid.link/20260424-rneri-fix-intel-pstate-doc-smt-asym-packing-v1-1-317bf7d5c362@linux.intel.com Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin