Revision tags: v6.6.67, v6.6.66, v6.6.65, v6.6.64, v6.6.63, v6.6.62, v6.6.61, v6.6.60 |
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e50e86db |
| 03-Nov-2024 |
Andrew Jeffery <andrew@codeconstruct.com.au> |
Merge tag 'v6.6.59' into for/openbmc/dev-6.6
This is the 6.6.59 stable release
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Revision tags: v6.6.59 |
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0d16f53c |
| 22-Oct-2024 |
Mateusz Guzik <mjguzik@gmail.com> |
exec: don't WARN for racy path_noexec check
[ Upstream commit 0d196e7589cefe207d5d41f37a0a28a1fdeeb7c6 ]
Both i_mode and noexec checks wrapped in WARN_ON stem from an artifact of the previous imple
exec: don't WARN for racy path_noexec check
[ Upstream commit 0d196e7589cefe207d5d41f37a0a28a1fdeeb7c6 ]
Both i_mode and noexec checks wrapped in WARN_ON stem from an artifact of the previous implementation. They used to legitimately check for the condition, but that got moved up in two commits: 633fb6ac3980 ("exec: move S_ISREG() check earlier") 0fd338b2d2cd ("exec: move path_noexec() check earlier")
Instead of being removed said checks are WARN_ON'ed instead, which has some debug value.
However, the spurious path_noexec check is racy, resulting in unwarranted warnings should someone race with setting the noexec flag.
One can note there is more to perm-checking whether execve is allowed and none of the conditions are guaranteed to still hold after they were tested for.
Additionally this does not validate whether the code path did any perm checking to begin with -- it will pass if the inode happens to be regular.
Keep the redundant path_noexec() check even though it's mindless nonsense checking for guarantee that isn't given so drop the WARN.
Reword the commentary and do small tidy ups while here.
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com> Link: https://lore.kernel.org/r/20240805131721.765484-1-mjguzik@gmail.com [brauner: keep redundant path_noexec() check] Signed-off-by: Christian Brauner <brauner@kernel.org> [cascardo: keep exit label and use it] Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@igalia.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
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Revision tags: v6.6.58, v6.6.57 |
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fac59652 |
| 10-Oct-2024 |
Andrew Jeffery <andrew@codeconstruct.com.au> |
Merge tag 'v6.6.56' into for/openbmc/dev-6.6
This is the 6.6.56 stable release
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Revision tags: v6.6.56, v6.6.55, v6.6.54, v6.6.53, v6.6.52, v6.6.51, v6.6.50 |
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a17dfde5 |
| 07-Sep-2024 |
Helge Deller <deller@gmx.de> |
parisc: Fix stack start for ADDR_NO_RANDOMIZE personality
commit f31b256994acec6929306dfa86ac29716e7503d6 upstream.
Fix the stack start address calculation for the parisc architecture in setup_arg_
parisc: Fix stack start for ADDR_NO_RANDOMIZE personality
commit f31b256994acec6929306dfa86ac29716e7503d6 upstream.
Fix the stack start address calculation for the parisc architecture in setup_arg_pages() when address randomization is disabled. When the ADDR_NO_RANDOMIZE process personality is disabled there is no need to add additional space for the stack. Note that this patch touches code inside an #ifdef CONFIG_STACK_GROWSUP hunk, which is why only the parisc architecture is affected since it's the only Linux architecture where the stack grows upwards.
Without this patch you will find the stack in the middle of some mapped libaries and suddenly limited to 6MB instead of 8MB:
root@parisc:~# setarch -R /bin/bash -c "cat /proc/self/maps" 00010000-00019000 r-xp 00000000 08:05 1182034 /usr/bin/cat 00019000-0001a000 rwxp 00009000 08:05 1182034 /usr/bin/cat 0001a000-0003b000 rwxp 00000000 00:00 0 [heap] f90c4000-f9283000 r-xp 00000000 08:05 1573004 /usr/lib/hppa-linux-gnu/libc.so.6 f9283000-f9285000 r--p 001bf000 08:05 1573004 /usr/lib/hppa-linux-gnu/libc.so.6 f9285000-f928a000 rwxp 001c1000 08:05 1573004 /usr/lib/hppa-linux-gnu/libc.so.6 f928a000-f9294000 rwxp 00000000 00:00 0 f9301000-f9323000 rwxp 00000000 00:00 0 [stack] f98b4000-f98e4000 r-xp 00000000 08:05 1572869 /usr/lib/hppa-linux-gnu/ld.so.1 f98e4000-f98e5000 r--p 00030000 08:05 1572869 /usr/lib/hppa-linux-gnu/ld.so.1 f98e5000-f98e9000 rwxp 00031000 08:05 1572869 /usr/lib/hppa-linux-gnu/ld.so.1 f9ad8000-f9b00000 rw-p 00000000 00:00 0 f9b00000-f9b01000 r-xp 00000000 00:00 0 [vdso]
With the patch the stack gets correctly mapped at the end of the process memory map:
root@panama:~# setarch -R /bin/bash -c "cat /proc/self/maps" 00010000-00019000 r-xp 00000000 08:13 16385582 /usr/bin/cat 00019000-0001a000 rwxp 00009000 08:13 16385582 /usr/bin/cat 0001a000-0003b000 rwxp 00000000 00:00 0 [heap] fef29000-ff0eb000 r-xp 00000000 08:13 16122400 /usr/lib/hppa-linux-gnu/libc.so.6 ff0eb000-ff0ed000 r--p 001c2000 08:13 16122400 /usr/lib/hppa-linux-gnu/libc.so.6 ff0ed000-ff0f2000 rwxp 001c4000 08:13 16122400 /usr/lib/hppa-linux-gnu/libc.so.6 ff0f2000-ff0fc000 rwxp 00000000 00:00 0 ff4b4000-ff4e4000 r-xp 00000000 08:13 16121913 /usr/lib/hppa-linux-gnu/ld.so.1 ff4e4000-ff4e6000 r--p 00030000 08:13 16121913 /usr/lib/hppa-linux-gnu/ld.so.1 ff4e6000-ff4ea000 rwxp 00032000 08:13 16121913 /usr/lib/hppa-linux-gnu/ld.so.1 ff6d7000-ff6ff000 rw-p 00000000 00:00 0 ff6ff000-ff700000 r-xp 00000000 00:00 0 [vdso] ff700000-ff722000 rwxp 00000000 00:00 0 [stack]
Reported-by: Camm Maguire <camm@maguirefamily.org> Signed-off-by: Helge Deller <deller@gmx.de> Fixes: d045c77c1a69 ("parisc,metag: Fix crashes due to stack randomization on stack-grows-upwards architectures") Fixes: 17d9822d4b4c ("parisc: Consider stack randomization for mmap base only when necessary") Cc: stable@vger.kernel.org # v5.2+ Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Revision tags: v6.6.49, v6.6.48 |
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1760371b |
| 19-Aug-2024 |
Andrew Jeffery <andrew@codeconstruct.com.au> |
Merge tag 'v6.6.47' into for/openbmc/dev-6.6
This is the 6.6.47 stable release
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Revision tags: v6.6.47, v6.6.46, v6.6.45 |
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d2a2a471 |
| 08-Aug-2024 |
Kees Cook <kees@kernel.org> |
exec: Fix ToCToU between perm check and set-uid/gid usage
commit f50733b45d865f91db90919f8311e2127ce5a0cb upstream.
When opening a file for exec via do_filp_open(), permission checking is done agai
exec: Fix ToCToU between perm check and set-uid/gid usage
commit f50733b45d865f91db90919f8311e2127ce5a0cb upstream.
When opening a file for exec via do_filp_open(), permission checking is done against the file's metadata at that moment, and on success, a file pointer is passed back. Much later in the execve() code path, the file metadata (specifically mode, uid, and gid) is used to determine if/how to set the uid and gid. However, those values may have changed since the permissions check, meaning the execution may gain unintended privileges.
For example, if a file could change permissions from executable and not set-id:
---------x 1 root root 16048 Aug 7 13:16 target
to set-id and non-executable:
---S------ 1 root root 16048 Aug 7 13:16 target
it is possible to gain root privileges when execution should have been disallowed.
While this race condition is rare in real-world scenarios, it has been observed (and proven exploitable) when package managers are updating the setuid bits of installed programs. Such files start with being world-executable but then are adjusted to be group-exec with a set-uid bit. For example, "chmod o-x,u+s target" makes "target" executable only by uid "root" and gid "cdrom", while also becoming setuid-root:
-rwxr-xr-x 1 root cdrom 16048 Aug 7 13:16 target
becomes:
-rwsr-xr-- 1 root cdrom 16048 Aug 7 13:16 target
But racing the chmod means users without group "cdrom" membership can get the permission to execute "target" just before the chmod, and when the chmod finishes, the exec reaches brpm_fill_uid(), and performs the setuid to root, violating the expressed authorization of "only cdrom group members can setuid to root".
Re-check that we still have execute permissions in case the metadata has changed. It would be better to keep a copy from the perm-check time, but until we can do that refactoring, the least-bad option is to do a full inode_permission() call (under inode lock). It is understood that this is safe against dead-locks, but hardly optimal.
Reported-by: Marco Vanotti <mvanotti@google.com> Tested-by: Marco Vanotti <mvanotti@google.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: stable@vger.kernel.org Cc: Eric Biederman <ebiederm@xmission.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Signed-off-by: Kees Cook <kees@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Revision tags: v6.6.44, v6.6.43, v6.6.42, v6.6.41, v6.6.40, v6.6.39, v6.6.38, v6.6.37, v6.6.36, v6.6.35, v6.6.34, v6.6.33, v6.6.32, v6.6.31, v6.6.30, v6.6.29, v6.6.28, v6.6.27, v6.6.26, v6.6.25 |
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46eeaa11 |
| 03-Apr-2024 |
Andrew Jeffery <andrew@codeconstruct.com.au> |
Merge tag 'v6.6.24' into dev-6.6
This is the 6.6.24 stable release
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Revision tags: v6.6.24, v6.6.23 |
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c3639d87 |
| 20-Mar-2024 |
Max Filippov <jcmvbkbc@gmail.com> |
exec: Fix NOMMU linux_binprm::exec in transfer_args_to_stack()
commit 2aea94ac14d1e0a8ae9e34febebe208213ba72f7 upstream.
In NOMMU kernel the value of linux_binprm::p is the offset inside the tempor
exec: Fix NOMMU linux_binprm::exec in transfer_args_to_stack()
commit 2aea94ac14d1e0a8ae9e34febebe208213ba72f7 upstream.
In NOMMU kernel the value of linux_binprm::p is the offset inside the temporary program arguments array maintained in separate pages in the linux_binprm::page. linux_binprm::exec being a copy of linux_binprm::p thus must be adjusted when that array is copied to the user stack. Without that adjustment the value passed by the NOMMU kernel to the ELF program in the AT_EXECFN entry of the aux array doesn't make any sense and it may break programs that try to access memory pointed to by that entry.
Adjust linux_binprm::exec before the successful return from the transfer_args_to_stack().
Cc: <stable@vger.kernel.org> Fixes: b6a2fea39318 ("mm: variable length argument support") Fixes: 5edc2a5123a7 ("binfmt_elf_fdpic: wire up AT_EXECFD, AT_EXECFN, AT_SECURE") Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> Link: https://lore.kernel.org/r/20240320182607.1472887-1-jcmvbkbc@gmail.com Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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7d7ae873 |
| 10-Feb-2024 |
Andrew Jeffery <andrew@codeconstruct.com.au> |
Merge tag 'v6.6.15' into dev-6.6
This is the 6.6.15 stable release
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Revision tags: v6.6.16, v6.6.15, v6.6.14 |
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841460c1 |
| 22-Jan-2024 |
Bernd Edlinger <bernd.edlinger@hotmail.de> |
exec: Fix error handling in begin_new_exec()
commit 84c39ec57d409e803a9bb6e4e85daf1243e0e80b upstream.
If get_unused_fd_flags() fails, the error handling is incomplete because bprm->cred is already
exec: Fix error handling in begin_new_exec()
commit 84c39ec57d409e803a9bb6e4e85daf1243e0e80b upstream.
If get_unused_fd_flags() fails, the error handling is incomplete because bprm->cred is already set to NULL, and therefore free_bprm will not unlock the cred_guard_mutex. Note there are two error conditions which end up here, one before and one after bprm->cred is cleared.
Fixes: b8a61c9e7b4a ("exec: Generic execfd support") Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de> Acked-by: Eric W. Biederman <ebiederm@xmission.com> Link: https://lore.kernel.org/r/AS8P193MB128517ADB5EFF29E04389EDAE4752@AS8P193MB1285.EURP193.PROD.OUTLOOK.COM Cc: stable@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Revision tags: v6.6.13, v6.6.12, v6.6.11, v6.6.10, v6.6.9, v6.6.8, v6.6.7, v6.6.6, v6.6.5, v6.6.4, v6.6.3, v6.6.2, v6.5.11, v6.6.1, v6.5.10, v6.6, v6.5.9, v6.5.8, v6.5.7, v6.5.6, v6.5.5, v6.5.4, v6.5.3 |
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c900529f |
| 12-Sep-2023 |
Thomas Zimmermann <tzimmermann@suse.de> |
Merge drm/drm-fixes into drm-misc-fixes
Forwarding to v6.6-rc1.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
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Revision tags: v6.5.2, v6.1.51, v6.5.1 |
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1ac731c5 |
| 30-Aug-2023 |
Dmitry Torokhov <dmitry.torokhov@gmail.com> |
Merge branch 'next' into for-linus
Prepare input updates for 6.6 merge window.
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Revision tags: v6.1.50 |
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d68b4b6f |
| 29-Aug-2023 |
Linus Torvalds <torvalds@linux-foundation.org> |
Merge tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-MM updates from Andrew Morton:
- An extensive rework of kexec and crash Kconfig from
Merge tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-MM updates from Andrew Morton:
- An extensive rework of kexec and crash Kconfig from Eric DeVolder ("refactor Kconfig to consolidate KEXEC and CRASH options")
- kernel.h slimming work from Andy Shevchenko ("kernel.h: Split out a couple of macros to args.h")
- gdb feature work from Kuan-Ying Lee ("Add GDB memory helper commands")
- vsprintf inclusion rationalization from Andy Shevchenko ("lib/vsprintf: Rework header inclusions")
- Switch the handling of kdump from a udev scheme to in-kernel handling, by Eric DeVolder ("crash: Kernel handling of CPU and memory hot un/plug")
- Many singleton patches to various parts of the tree
* tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (81 commits) document while_each_thread(), change first_tid() to use for_each_thread() drivers/char/mem.c: shrink character device's devlist[] array x86/crash: optimize CPU changes crash: change crash_prepare_elf64_headers() to for_each_possible_cpu() crash: hotplug support for kexec_load() x86/crash: add x86 crash hotplug support crash: memory and CPU hotplug sysfs attributes kexec: exclude elfcorehdr from the segment digest crash: add generic infrastructure for crash hotplug support crash: move a few code bits to setup support of crash hotplug kstrtox: consistently use _tolower() kill do_each_thread() nilfs2: fix WARNING in mark_buffer_dirty due to discarded buffer reuse scripts/bloat-o-meter: count weak symbol sizes treewide: drop CONFIG_EMBEDDED lockdep: fix static memory detection even more lib/vsprintf: declare no_hash_pointers in sprintf.h lib/vsprintf: split out sprintf() and friends kernel/fork: stop playing lockless games for exe_file replacement adfs: delete unused "union adfs_dirtail" definition ...
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b96a3e91 |
| 29-Aug-2023 |
Linus Torvalds <torvalds@linux-foundation.org> |
Merge tag 'mm-stable-2023-08-28-18-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- Some swap cleanups from Ma Wupeng ("fix WARN_ON in add_to_a
Merge tag 'mm-stable-2023-08-28-18-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- Some swap cleanups from Ma Wupeng ("fix WARN_ON in add_to_avail_list")
- Peter Xu has a series (mm/gup: Unify hugetlb, speed up thp") which reduces the special-case code for handling hugetlb pages in GUP. It also speeds up GUP handling of transparent hugepages.
- Peng Zhang provides some maple tree speedups ("Optimize the fast path of mas_store()").
- Sergey Senozhatsky has improved te performance of zsmalloc during compaction (zsmalloc: small compaction improvements").
- Domenico Cerasuolo has developed additional selftest code for zswap ("selftests: cgroup: add zswap test program").
- xu xin has doe some work on KSM's handling of zero pages. These changes are mainly to enable the user to better understand the effectiveness of KSM's treatment of zero pages ("ksm: support tracking KSM-placed zero-pages").
- Jeff Xu has fixes the behaviour of memfd's MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED sysctl ("mm/memfd: fix sysctl MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED").
- David Howells has fixed an fscache optimization ("mm, netfs, fscache: Stop read optimisation when folio removed from pagecache").
- Axel Rasmussen has given userfaultfd the ability to simulate memory poisoning ("add UFFDIO_POISON to simulate memory poisoning with UFFD").
- Miaohe Lin has contributed some routine maintenance work on the memory-failure code ("mm: memory-failure: remove unneeded PageHuge() check").
- Peng Zhang has contributed some maintenance work on the maple tree code ("Improve the validation for maple tree and some cleanup").
- Hugh Dickins has optimized the collapsing of shmem or file pages into THPs ("mm: free retracted page table by RCU").
- Jiaqi Yan has a patch series which permits us to use the healthy subpages within a hardware poisoned huge page for general purposes ("Improve hugetlbfs read on HWPOISON hugepages").
- Kemeng Shi has done some maintenance work on the pagetable-check code ("Remove unused parameters in page_table_check").
- More folioification work from Matthew Wilcox ("More filesystem folio conversions for 6.6"), ("Followup folio conversions for zswap"). And from ZhangPeng ("Convert several functions in page_io.c to use a folio").
- page_ext cleanups from Kemeng Shi ("minor cleanups for page_ext").
- Baoquan He has converted some architectures to use the GENERIC_IOREMAP ioremap()/iounmap() code ("mm: ioremap: Convert architectures to take GENERIC_IOREMAP way").
- Anshuman Khandual has optimized arm64 tlb shootdown ("arm64: support batched/deferred tlb shootdown during page reclamation/migration").
- Better maple tree lockdep checking from Liam Howlett ("More strict maple tree lockdep"). Liam also developed some efficiency improvements ("Reduce preallocations for maple tree").
- Cleanup and optimization to the secondary IOMMU TLB invalidation, from Alistair Popple ("Invalidate secondary IOMMU TLB on permission upgrade").
- Ryan Roberts fixes some arm64 MM selftest issues ("selftests/mm fixes for arm64").
- Kemeng Shi provides some maintenance work on the compaction code ("Two minor cleanups for compaction").
- Some reduction in mmap_lock pressure from Matthew Wilcox ("Handle most file-backed faults under the VMA lock").
- Aneesh Kumar contributes code to use the vmemmap optimization for DAX on ppc64, under some circumstances ("Add support for DAX vmemmap optimization for ppc64").
- page-ext cleanups from Kemeng Shi ("add page_ext_data to get client data in page_ext"), ("minor cleanups to page_ext header").
- Some zswap cleanups from Johannes Weiner ("mm: zswap: three cleanups").
- kmsan cleanups from ZhangPeng ("minor cleanups for kmsan").
- VMA handling cleanups from Kefeng Wang ("mm: convert to vma_is_initial_heap/stack()").
- DAMON feature work from SeongJae Park ("mm/damon/sysfs-schemes: implement DAMOS tried total bytes file"), ("Extend DAMOS filters for address ranges and DAMON monitoring targets").
- Compaction work from Kemeng Shi ("Fixes and cleanups to compaction").
- Liam Howlett has improved the maple tree node replacement code ("maple_tree: Change replacement strategy").
- ZhangPeng has a general code cleanup - use the K() macro more widely ("cleanup with helper macro K()").
- Aneesh Kumar brings memmap-on-memory to ppc64 ("Add support for memmap on memory feature on ppc64").
- pagealloc cleanups from Kemeng Shi ("Two minor cleanups for pcp list in page_alloc"), ("Two minor cleanups for get pageblock migratetype").
- Vishal Moola introduces a memory descriptor for page table tracking, "struct ptdesc" ("Split ptdesc from struct page").
- memfd selftest maintenance work from Aleksa Sarai ("memfd: cleanups for vm.memfd_noexec").
- MM include file rationalization from Hugh Dickins ("arch: include asm/cacheflush.h in asm/hugetlb.h").
- THP debug output fixes from Hugh Dickins ("mm,thp: fix sloppy text output").
- kmemleak improvements from Xiaolei Wang ("mm/kmemleak: use object_cache instead of kmemleak_initialized").
- More folio-related cleanups from Matthew Wilcox ("Remove _folio_dtor and _folio_order").
- A VMA locking scalability improvement from Suren Baghdasaryan ("Per-VMA lock support for swap and userfaults").
- pagetable handling cleanups from Matthew Wilcox ("New page table range API").
- A batch of swap/thp cleanups from David Hildenbrand ("mm/swap: stop using page->private on tail pages for THP_SWAP + cleanups").
- Cleanups and speedups to the hugetlb fault handling from Matthew Wilcox ("Change calling convention for ->huge_fault").
- Matthew Wilcox has also done some maintenance work on the MM subsystem documentation ("Improve mm documentation").
* tag 'mm-stable-2023-08-28-18-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (489 commits) maple_tree: shrink struct maple_tree maple_tree: clean up mas_wr_append() secretmem: convert page_is_secretmem() to folio_is_secretmem() nios2: fix flush_dcache_page() for usage from irq context hugetlb: add documentation for vma_kernel_pagesize() mm: add orphaned kernel-doc to the rst files. mm: fix clean_record_shared_mapping_range kernel-doc mm: fix get_mctgt_type() kernel-doc mm: fix kernel-doc warning from tlb_flush_rmaps() mm: remove enum page_entry_size mm: allow ->huge_fault() to be called without the mmap_lock held mm: move PMD_ORDER to pgtable.h mm: remove checks for pte_index memcg: remove duplication detection for mem_cgroup_uncharge_swap mm/huge_memory: work on folio->swap instead of page->private when splitting folio mm/swap: inline folio_set_swap_entry() and folio_swap_entry() mm/swap: use dedicated entry for swap in folio mm/swap: stop using page->private on tail pages for THP_SWAP selftests/mm: fix WARNING comparing pointer to 0 selftests: cgroup: fix test_kmem_memcg_deletion kernel mem check ...
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Revision tags: v6.5, v6.1.49, v6.1.48, v6.1.46 |
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a7031f14 |
| 14-Aug-2023 |
Mateusz Guzik <mjguzik@gmail.com> |
kernel/fork: stop playing lockless games for exe_file replacement
xchg originated in 6e399cd144d8 ("prctl: avoid using mmap_sem for exe_file serialization"). While the commit message does not expla
kernel/fork: stop playing lockless games for exe_file replacement
xchg originated in 6e399cd144d8 ("prctl: avoid using mmap_sem for exe_file serialization"). While the commit message does not explain *why* the change, I found the original submission [1] which ultimately claims it cleans things up by removing dependency of exe_file on the semaphore.
However, fe69d560b5bd ("kernel/fork: always deny write access to current MM exe_file") added a semaphore up/down cycle to synchronize the state of exe_file against fork, defeating the point of the original change.
This is on top of semaphore trips already present both in the replacing function and prctl (the only consumer).
Normally replacing exe_file does not happen for busy processes, thus write-locking is not an impediment to performance in the intended use case. If someone keeps invoking the routine for a busy processes they are trying to play dirty and that's another reason to avoid any trickery.
As such I think the atomic here only adds complexity for no benefit.
Just write-lock around the replacement.
I also note that replacement races against the mapping check loop as nothing synchronizes actual assignment with with said checks but I am not addressing it in this patch. (Is the loop of any use to begin with?)
Link: https://lore.kernel.org/linux-mm/1424979417.10344.14.camel@stgolabs.net/ [1] Link: https://lkml.kernel.org/r/20230814172140.1777161-1-mjguzik@gmail.com Signed-off-by: Mateusz Guzik <mjguzik@gmail.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: "Christian Brauner (Microsoft)" <brauner@kernel.org> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mateusz Guzik <mjguzik@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Revision tags: v6.1.45, v6.1.44, v6.1.43, v6.1.42 |
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b5df0922 |
| 24-Jul-2023 |
Liam R. Howlett <Liam.Howlett@oracle.com> |
mm: set up vma iterator for vma_iter_prealloc() calls
Set the correct limits for vma_iter_prealloc() calls so that the maple tree can be smarter about how many nodes are needed.
Link: https://lkml.
mm: set up vma iterator for vma_iter_prealloc() calls
Set the correct limits for vma_iter_prealloc() calls so that the maple tree can be smarter about how many nodes are needed.
Link: https://lkml.kernel.org/r/20230724183157.3939892-11-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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2612e3bb |
| 07-Aug-2023 |
Rodrigo Vivi <rodrigo.vivi@intel.com> |
Merge drm/drm-next into drm-intel-next
Catching-up with drm-next and drm-intel-gt-next. It will unblock a code refactor around the platform definitions (names vs acronyms).
Signed-off-by: Rodrigo V
Merge drm/drm-next into drm-intel-next
Catching-up with drm-next and drm-intel-gt-next. It will unblock a code refactor around the platform definitions (names vs acronyms).
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
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9f771739 |
| 07-Aug-2023 |
Joonas Lahtinen <joonas.lahtinen@linux.intel.com> |
Merge drm/drm-next into drm-intel-gt-next
Need to pull in b3e4aae612ec ("drm/i915/hdcp: Modify hdcp_gsc_message msg sending mechanism") as a dependency for https://patchwork.freedesktop.org/series/1
Merge drm/drm-next into drm-intel-gt-next
Need to pull in b3e4aae612ec ("drm/i915/hdcp: Modify hdcp_gsc_message msg sending mechanism") as a dependency for https://patchwork.freedesktop.org/series/121735/
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
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Revision tags: v6.1.41 |
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61b73694 |
| 24-Jul-2023 |
Thomas Zimmermann <tzimmermann@suse.de> |
Merge drm/drm-next into drm-misc-next
Backmerging to get v6.5-rc2.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
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Revision tags: v6.1.40, v6.1.39 |
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50501936 |
| 17-Jul-2023 |
Dmitry Torokhov <dmitry.torokhov@gmail.com> |
Merge tag 'v6.4' into next
Sync up with mainline to bring in updates to shared infrastructure.
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0791faeb |
| 17-Jul-2023 |
Mark Brown <broonie@kernel.org> |
ASoC: Merge v6.5-rc2
Get a similar baseline to my other branches, and fixes for people using the branch.
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2f98e686 |
| 11-Jul-2023 |
Maxime Ripard <mripard@kernel.org> |
Merge v6.5-rc1 into drm-misc-fixes
Boris needs 6.5-rc1 in drm-misc-fixes to prevent a conflict.
Signed-off-by: Maxime Ripard <mripard@kernel.org>
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Revision tags: v6.1.38, v6.1.37 |
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44f10dbe |
| 30-Jun-2023 |
Andrew Morton <akpm@linux-foundation.org> |
Merge branch 'master' into mm-hotfixes-stable
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18c9901d |
| 29-Jun-2023 |
Linus Torvalds <torvalds@linux-foundation.org> |
Merge tag 'fsnotify_for_v6.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
Pull fsnotify updates from Jan Kara:
- Support for fanotify events returning file handles for files
Merge tag 'fsnotify_for_v6.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
Pull fsnotify updates from Jan Kara:
- Support for fanotify events returning file handles for filesystems not exportable via NFS
- Improved error handling exportfs functions
- Add missing FS_OPEN events when unusual open helpers are used
* tag 'fsnotify_for_v6.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs: fsnotify: move fsnotify_open() hook into do_dentry_open() exportfs: check for error return value from exportfs_encode_*() fanotify: support reporting non-decodeable file handles exportfs: allow exporting non-decodeable file handles to userspace exportfs: add explicit flag to request non-decodeable file handles exportfs: change connectable argument to bit flags
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9471f1f2 |
| 28-Jun-2023 |
Linus Torvalds <torvalds@linux-foundation.org> |
Merge branch 'expand-stack'
This modifies our user mode stack expansion code to always take the mmap_lock for writing before modifying the VM layout.
It's actually something we always technically s
Merge branch 'expand-stack'
This modifies our user mode stack expansion code to always take the mmap_lock for writing before modifying the VM layout.
It's actually something we always technically should have done, but because we didn't strictly need it, we were being lazy ("opportunistic" sounds so much better, doesn't it?) about things, and had this hack in place where we would extend the stack vma in-place without doing the proper locking.
And it worked fine. We just needed to change vm_start (or, in the case of grow-up stacks, vm_end) and together with some special ad-hoc locking using the anon_vma lock and the mm->page_table_lock, it all was fairly straightforward.
That is, it was all fine until Ruihan Li pointed out that now that the vma layout uses the maple tree code, we *really* don't just change vm_start and vm_end any more, and the locking really is broken. Oops.
It's not actually all _that_ horrible to fix this once and for all, and do proper locking, but it's a bit painful. We have basically three different cases of stack expansion, and they all work just a bit differently:
- the common and obvious case is the page fault handling. It's actually fairly simple and straightforward, except for the fact that we have something like 24 different versions of it, and you end up in a maze of twisty little passages, all alike.
- the simplest case is the execve() code that creates a new stack. There are no real locking concerns because it's all in a private new VM that hasn't been exposed to anybody, but lockdep still can end up unhappy if you get it wrong.
- and finally, we have GUP and page pinning, which shouldn't really be expanding the stack in the first place, but in addition to execve() we also use it for ptrace(). And debuggers do want to possibly access memory under the stack pointer and thus need to be able to expand the stack as a special case.
None of these cases are exactly complicated, but the page fault case in particular is just repeated slightly differently many many times. And ia64 in particular has a fairly complicated situation where you can have both a regular grow-down stack _and_ a special grow-up stack for the register backing store.
So to make this slightly more manageable, the bulk of this series is to first create a helper function for the most common page fault case, and convert all the straightforward architectures to it.
Thus the new 'lock_mm_and_find_vma()' helper function, which ends up being used by x86, arm, powerpc, mips, riscv, alpha, arc, csky, hexagon, loongarch, nios2, sh, sparc32, and xtensa. So we not only convert more than half the architectures, we now have more shared code and avoid some of those twisty little passages.
And largely due to this common helper function, the full diffstat of this series ends up deleting more lines than it adds.
That still leaves eight architectures (ia64, m68k, microblaze, openrisc, parisc, s390, sparc64 and um) that end up doing 'expand_stack()' manually because they are doing something slightly different from the normal pattern. Along with the couple of special cases in execve() and GUP.
So there's a couple of patches that first create 'locked' helper versions of the stack expansion functions, so that there's a obvious path forward in the conversion. The execve() case is then actually pretty simple, and is a nice cleanup from our old "grow-up stackls are special, because at execve time even they grow down".
The #ifdef CONFIG_STACK_GROWSUP in that code just goes away, because it's just more straightforward to write out the stack expansion there manually, instead od having get_user_pages_remote() do it for us in some situations but not others and have to worry about locking rules for GUP.
And the final step is then to just convert the remaining odd cases to a new world order where 'expand_stack()' is called with the mmap_lock held for reading, but where it might drop it and upgrade it to a write, only to return with it held for reading (in the success case) or with it completely dropped (in the failure case).
In the process, we remove all the stack expansion from GUP (where dropping the lock wouldn't be ok without special rules anyway), and add it in manually to __access_remote_vm() for ptrace().
Thanks to Adrian Glaubitz and Frank Scheiner who tested the ia64 cases. Everything else here felt pretty straightforward, but the ia64 rules for stack expansion are really quite odd and very different from everything else. Also thanks to Vegard Nossum who caught me getting one of those odd conditions entirely the wrong way around.
Anyway, I think I want to actually move all the stack expansion code to a whole new file of its own, rather than have it split up between mm/mmap.c and mm/memory.c, but since this will have to be backported to the initial maple tree vma introduction anyway, I tried to keep the patches _fairly_ minimal.
Also, while I don't think it's valid to expand the stack from GUP, the final patch in here is a "warn if some crazy GUP user wants to try to expand the stack" patch. That one will be reverted before the final release, but it's left to catch any odd cases during the merge window and release candidates.
Reported-by: Ruihan Li <lrh2000@pku.edu.cn>
* branch 'expand-stack': gup: add warning if some caller would seem to want stack expansion mm: always expand the stack with the mmap write lock held execve: expand new process stack manually ahead of time mm: make find_extend_vma() fail if write lock not held powerpc/mm: convert coprocessor fault to lock_mm_and_find_vma() mm/fault: convert remaining simple cases to lock_mm_and_find_vma() arm/mm: Convert to using lock_mm_and_find_vma() riscv/mm: Convert to using lock_mm_and_find_vma() mips/mm: Convert to using lock_mm_and_find_vma() powerpc/mm: Convert to using lock_mm_and_find_vma() arm64/mm: Convert to using lock_mm_and_find_vma() mm: make the page fault mmap locking killable mm: introduce new 'lock_mm_and_find_vma()' page fault helper
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