user/sven/linux.git/fs/proc, branch v6.9.9

fs/proc: fix softlockup in __read_vmcore

2024-06-21T12:40:33Z

commit 5cbcb62dddf5346077feb82b7b0c9254222d3445 upstream. While taking a kernel core dump with makedumpfile on a larger system, softlockup messages often appear. While softlockup warnings can be harmless, they can also interfere with things like RCU freeing memory, which can be problematic when the kdump kexec image is configured with as little memory as possible. Avoid the softlockup, and give things like work items and RCU a chance to do their thing during __read_vmcore by adding a cond_resched. Link: https://lkml.kernel.org/r/20240507091858.36ff767f@imladris.surriel.com Signed-off-by: Rik van Riel Acked-by: Baoquan He Cc: Dave Young Cc: Vivek Goyal Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

mm: /proc/pid/smaps_rollup: avoid skipping vma after getting mmap_lock again

2024-06-16T11:51:07Z

commit 6d065f507d82307d6161ac75c025111fb8b08a46 upstream. After switching smaps_rollup to use VMA iterator, searching for next entry is part of the condition expression of the do-while loop. So the current VMA needs to be addressed before the continue statement. Otherwise, with some VMAs skipped, userspace observed memory consumption from /proc/pid/smaps_rollup will be smaller than the sum of the corresponding fields from /proc/pid/smaps. Link: https://lkml.kernel.org/r/20240523183531.2535436-1-yzhong@purestorage.com Fixes: c4c84f06285e ("fs/proc/task_mmu: stop using linked list and highest_vm_end") Signed-off-by: Yuanyuan Zhong Reviewed-by: Mohamed Khalfella Cc: David Hildenbrand Cc: Matthew Wilcox (Oracle) Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

mm/ksm: fix ksm_zero_pages accounting

2024-06-16T11:51:06Z

commit c2dc78b86e0821ecf9a9d0c35dba2618279a5bb6 upstream. We normally ksm_zero_pages++ in ksmd when page is merged with zero page, but ksm_zero_pages-- is done from page tables side, where there is no any accessing protection of ksm_zero_pages. So we can read very exceptional value of ksm_zero_pages in rare cases, such as -1, which is very confusing to users. Fix it by changing to use atomic_long_t, and the same case with the mm->ksm_zero_pages. Link: https://lkml.kernel.org/r/20240528-b4-ksm-counters-v3-2-34bb358fdc13@linux.dev Fixes: e2942062e01d ("ksm: count all zero pages placed by KSM") Fixes: 6080d19f0704 ("ksm: add ksm zero pages for each process") Signed-off-by: Chengming Zhou Acked-by: David Hildenbrand Cc: Andrea Arcangeli Cc: Hugh Dickins Cc: Ran Xiaokai Cc: Stefan Roesch Cc: xu xin Cc: Yang Yang Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

proc: Move fdinfo PTRACE_MODE_READ check into the inode .permission operation

2024-06-16T11:50:56Z

commit 0a960ba49869ebe8ff859d000351504dd6b93b68 upstream. The following commits loosened the permissions of /proc//fdinfo/ directory, as well as the files within it, from 0500 to 0555 while also introducing a PTRACE_MODE_READ check between the current task and 's task: - commit 7bc3fa0172a4 ("procfs: allow reading fdinfo with PTRACE_MODE_READ") - commit 1927e498aee1 ("procfs: prevent unprivileged processes accessing fdinfo dir") Before those changes, inode based system calls like inotify_add_watch(2) would fail when the current task didn't have sufficient read permissions: [...] lstat("/proc/1/task/1/fdinfo", {st_mode=S_IFDIR|0500, st_size=0, ...}) = 0 inotify_add_watch(64, "/proc/1/task/1/fdinfo", IN_MODIFY|IN_ATTRIB|IN_MOVED_FROM|IN_MOVED_TO|IN_CREATE|IN_DELETE| IN_ONLYDIR|IN_DONT_FOLLOW|IN_EXCL_UNLINK) = -1 EACCES (Permission denied) [...] This matches the documented behavior in the inotify_add_watch(2) man page: ERRORS EACCES Read access to the given file is not permitted. After those changes, inotify_add_watch(2) started succeeding despite the current task not having PTRACE_MODE_READ privileges on the target task: [...] lstat("/proc/1/task/1/fdinfo", {st_mode=S_IFDIR|0555, st_size=0, ...}) = 0 inotify_add_watch(64, "/proc/1/task/1/fdinfo", IN_MODIFY|IN_ATTRIB|IN_MOVED_FROM|IN_MOVED_TO|IN_CREATE|IN_DELETE| IN_ONLYDIR|IN_DONT_FOLLOW|IN_EXCL_UNLINK) = 1757 openat(AT_FDCWD, "/proc/1/task/1/fdinfo", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = -1 EACCES (Permission denied) [...] This change in behavior broke .NET prior to v7. See the github link below for the v7 commit that inadvertently/quietly (?) fixed .NET after the kernel changes mentioned above. Return to the old behavior by moving the PTRACE_MODE_READ check out of the file .open operation and into the inode .permission operation: [...] lstat("/proc/1/task/1/fdinfo", {st_mode=S_IFDIR|0555, st_size=0, ...}) = 0 inotify_add_watch(64, "/proc/1/task/1/fdinfo", IN_MODIFY|IN_ATTRIB|IN_MOVED_FROM|IN_MOVED_TO|IN_CREATE|IN_DELETE| IN_ONLYDIR|IN_DONT_FOLLOW|IN_EXCL_UNLINK) = -1 EACCES (Permission denied) [...] Reported-by: Kevin Parsons (Microsoft) Link: https://github.com/dotnet/runtime/commit/89e5469ac591b82d38510fe7de98346cce74ad4f Link: https://stackoverflow.com/questions/75379065/start-self-contained-net6-build-exe-as-service-on-raspbian-system-unauthorizeda Fixes: 7bc3fa0172a4 ("procfs: allow reading fdinfo with PTRACE_MODE_READ") Cc: stable@vger.kernel.org Cc: Christian Brauner Cc: Christian König Cc: Jann Horn Cc: Kalesh Singh Cc: Hardik Garg Cc: Allen Pais Signed-off-by: Tyler Hicks (Microsoft) Link: https://lore.kernel.org/r/20240501005646.745089-1-code@tyhicks.com Signed-off-by: Christian Brauner Signed-off-by: Greg Kroah-Hartman

fs/proc/task_mmu: fix uffd-wp confusion in pagemap_scan_pmd_entry()

2024-05-06T00:28:07Z

pagemap_scan_pmd_entry() checks if uffd-wp is set on each pte to avoid unnecessary if set. However it was previously checking with `pte_uffd_wp(ptep_get(pte))` without first confirming that the pte was present. It is only valid to call pte_uffd_wp() for present ptes. For swap ptes, pte_swp_uffd_wp() must be called because the uffd-wp bit may be kept in a different position, depending on the arch. This was leading to test failures in the pagemap_ioctl mm selftest, when bringing up uffd-wp support on arm64 due to incorrectly interpretting the uffd-wp status of migration entries. Let's fix this by using the correct check based on pte_present(). While we are at it, let's pass the pte to make_uffd_wp_pte() to avoid the pointless extra ptep_get() which can't be optimized out due to READ_ONCE() on many arches. Link: https://lkml.kernel.org/r/20240429114104.182890-1-ryan.roberts@arm.com Fixes: 12f6b01a0bcb ("fs/proc/task_mmu: add fast paths to get/clear PAGE_IS_WRITTEN flag") Closes: https://lore.kernel.org/linux-arm-kernel/ZiuyGXt0XWwRgFh9@x1n/ Signed-off-by: Ryan Roberts Acked-by: David Hildenbrand Reviewed-by: Muhammad Usama Anjum Tested-by: Muhammad Usama Anjum Cc: Peter Xu Cc: Signed-off-by: Andrew Morton

fs/proc/task_mmu: fix loss of young/dirty bits during pagemap scan

2024-05-06T00:28:06Z

make_uffd_wp_pte() was previously doing: pte = ptep_get(ptep); ptep_modify_prot_start(ptep); pte = pte_mkuffd_wp(pte); ptep_modify_prot_commit(ptep, pte); But if another thread accessed or dirtied the pte between the first 2 calls, this could lead to loss of that information. Since ptep_modify_prot_start() gets and clears atomically, the following is the correct pattern and prevents any possible race. Any access after the first call would see an invalid pte and cause a fault: pte = ptep_modify_prot_start(ptep); pte = pte_mkuffd_wp(pte); ptep_modify_prot_commit(ptep, pte); Link: https://lkml.kernel.org/r/20240429114017.182570-1-ryan.roberts@arm.com Fixes: 52526ca7fdb9 ("fs/proc/task_mmu: implement IOCTL to get and optionally clear info about PTEs") Signed-off-by: Ryan Roberts Acked-by: David Hildenbrand Cc: Muhammad Usama Anjum Cc: Peter Xu Cc: Signed-off-by: Andrew Morton

mm: support page_mapcount() on page_has_type() pages

2024-04-25T02:34:26Z

Return 0 for pages which can't be mapped. This matches how page_mapped() works. It is more convenient for users to not have to filter out these pages. Link: https://lkml.kernel.org/r/20240321142448.1645400-5-willy@infradead.org Fixes: 9c5ccf2db04b ("mm: remove HUGETLB_PAGE_DTOR") Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: David Hildenbrand Acked-by: Vlastimil Babka Cc: Miaohe Lin Cc: Muchun Song Cc: Oscar Salvador Cc: Signed-off-by: Andrew Morton

fs/proc: Skip bootloader comment if no embedded kernel parameters

2024-04-09T14:36:18Z

If the "bootconfig" kernel command-line argument was specified or if the kernel was built with CONFIG_BOOT_CONFIG_FORCE, but if there are no embedded kernel parameter, omit the "# Parameters from bootloader:" comment from the /proc/bootconfig file. This will cause automation to fall back to the /proc/cmdline file, which will be identical to the comment in this no-embedded-kernel-parameters case. Link: https://lore.kernel.org/all/20240409044358.1156477-2-paulmck@kernel.org/ Fixes: 8b8ce6c75430 ("fs/proc: remove redundant comments from /proc/bootconfig") Signed-off-by: Masami Hiramatsu Signed-off-by: Paul E. McKenney Cc: stable@vger.kernel.org Acked-by: Masami Hiramatsu (Google) Signed-off-by: Masami Hiramatsu (Google)

fs/proc: remove redundant comments from /proc/bootconfig

2024-04-09T14:31:54Z

commit 717c7c894d4b ("fs/proc: Add boot loader arguments as comment to /proc/bootconfig") adds bootloader argument comments into /proc/bootconfig. /proc/bootconfig shows boot_command_line[] multiple times following every xbc key value pair, that's duplicated and not necessary. Remove redundant ones. Output before and after the fix is like: key1 = value1 *bootloader argument comments* key2 = value2 *bootloader argument comments* key3 = value3 *bootloader argument comments* ... key1 = value1 key2 = value2 key3 = value3 *bootloader argument comments* ... Link: https://lore.kernel.org/all/20240409044358.1156477-1-paulmck@kernel.org/ Fixes: 717c7c894d4b ("fs/proc: Add boot loader arguments as comment to /proc/bootconfig") Signed-off-by: Zhenhua Huang Signed-off-by: Paul E. McKenney Cc: Cc: Cc: stable@vger.kernel.org Acked-by: Masami Hiramatsu (Google) Signed-off-by: Masami Hiramatsu (Google)

kbuild: make -Woverride-init warnings more consistent

2024-03-31T02:32:26Z

The -Woverride-init warn about code that may be intentional or not, but the inintentional ones tend to be real bugs, so there is a bit of disagreement on whether this warning option should be enabled by default and we have multiple settings in scripts/Makefile.extrawarn as well as individual subsystems. Older versions of clang only supported -Wno-initializer-overrides with the same meaning as gcc's -Woverride-init, though all supported versions now work with both. Because of this difference, an earlier cleanup of mine accidentally turned the clang warning off for W=1 builds and only left it on for W=2, while it's still enabled for gcc with W=1. There is also one driver that only turns the warning off for newer versions of gcc but not other compilers, and some but not all the Makefiles still use a cc-disable-warning conditional that is no longer needed with supported compilers here. Address all of the above by removing the special cases for clang and always turning the warning off unconditionally where it got in the way, using the syntax that is supported by both compilers. Fixes: 2cd3271b7a31 ("kbuild: avoid duplicate warning options") Signed-off-by: Arnd Bergmann Acked-by: Hamza Mahfooz Acked-by: Jani Nikula Acked-by: Andrew Jeffery Signed-off-by: Jani Nikula Reviewed-by: Linus Walleij Signed-off-by: Masahiro Yamada