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11 daysunshare: fix unshare_fs() handlingAl Viro1-1/+1
[ Upstream commit 6c4b2243cb6c0755159bd567130d5e12e7b10d9f ] There's an unpleasant corner case in unshare(2), when we have a CLONE_NEWNS in flags and current->fs hadn't been shared at all; in that case copy_mnt_ns() gets passed current->fs instead of a private copy, which causes interesting warts in proof of correctness] > I guess if private means fs->users == 1, the condition could still be true. Unfortunately, it's worse than just a convoluted proof of correctness. Consider the case when we have CLONE_NEWCGROUP in addition to CLONE_NEWNS (and current->fs->users == 1). We pass current->fs to copy_mnt_ns(), all right. Suppose it succeeds and flips current->fs->{pwd,root} to corresponding locations in the new namespace. Now we proceed to copy_cgroup_ns(), which fails (e.g. with -ENOMEM). We call put_mnt_ns() on the namespace created by copy_mnt_ns(), it's destroyed and its mount tree is dissolved, but... current->fs->root and current->fs->pwd are both left pointing to now detached mounts. They are pinning those, so it's not a UAF, but it leaves the calling process with unshare(2) failing with -ENOMEM _and_ leaving it with pwd and root on detached isolated mounts. The last part is clearly a bug. There is other fun related to that mess (races with pivot_root(), including the one between pivot_root() and fork(), of all things), but this one is easy to isolate and fix - treat CLONE_NEWNS as "allocate a new fs_struct even if it hadn't been shared in the first place". Sure, we could go for something like "if both CLONE_NEWNS *and* one of the things that might end up failing after copy_mnt_ns() call in create_new_namespaces() are set, force allocation of new fs_struct", but let's keep it simple - the cost of copy_fs_struct() is trivial. Another benefit is that copy_mnt_ns() with CLONE_NEWNS *always* gets a freshly allocated fs_struct, yet to be attached to anything. That seriously simplifies the analysis... FWIW, that bug had been there since the introduction of unshare(2) ;-/ Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Link: https://patch.msgid.link/20260207082524.GE3183987@ZenIV Tested-by: Waiman Long <longman@redhat.com> Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-10-19copy_sighand: Handle architectures where sizeof(unsigned long) < sizeof(u64)Simon Schuster1-1/+1
commit 04ff48239f46e8b493571e260bd0e6c3a6400371 upstream. With the introduction of clone3 in commit 7f192e3cd316 ("fork: add clone3") the effective bit width of clone_flags on all architectures was increased from 32-bit to 64-bit. However, the signature of the copy_* helper functions (e.g., copy_sighand) used by copy_process was not adapted. As such, they truncate the flags on any 32-bit architectures that supports clone3 (arc, arm, csky, m68k, microblaze, mips32, openrisc, parisc32, powerpc32, riscv32, x86-32 and xtensa). For copy_sighand with CLONE_CLEAR_SIGHAND being an actual u64 constant, this triggers an observable bug in kernel selftest clone3_clear_sighand: if (clone_flags & CLONE_CLEAR_SIGHAND) in function copy_sighand within fork.c will always fail given: unsigned long /* == uint32_t */ clone_flags #define CLONE_CLEAR_SIGHAND 0x100000000ULL This commit fixes the bug by always passing clone_flags to copy_sighand via their declared u64 type, invariant of architecture-dependent integer sizes. Fixes: b612e5df4587 ("clone3: add CLONE_CLEAR_SIGHAND") Cc: stable@vger.kernel.org # linux-5.5+ Signed-off-by: Simon Schuster <schuster.simon@siemens-energy.com> Link: https://lore.kernel.org/20250901-nios2-implement-clone3-v2-1-53fcf5577d57@siemens-energy.com Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-08-28mm: drop the assumption that VM_SHARED always implies writableIsaac J. Manjarres1-1/+1
From: Lorenzo Stoakes <lstoakes@gmail.com> [ Upstream commit e8e17ee90eaf650c855adb0a3e5e965fd6692ff1 ] Patch series "permit write-sealed memfd read-only shared mappings", v4. The man page for fcntl() describing memfd file seals states the following about F_SEAL_WRITE:- Furthermore, trying to create new shared, writable memory-mappings via mmap(2) will also fail with EPERM. With emphasis on 'writable'. In turns out in fact that currently the kernel simply disallows all new shared memory mappings for a memfd with F_SEAL_WRITE applied, rendering this documentation inaccurate. This matters because users are therefore unable to obtain a shared mapping to a memfd after write sealing altogether, which limits their usefulness. This was reported in the discussion thread [1] originating from a bug report [2]. This is a product of both using the struct address_space->i_mmap_writable atomic counter to determine whether writing may be permitted, and the kernel adjusting this counter when any VM_SHARED mapping is performed and more generally implicitly assuming VM_SHARED implies writable. It seems sensible that we should only update this mapping if VM_MAYWRITE is specified, i.e. whether it is possible that this mapping could at any point be written to. If we do so then all we need to do to permit write seals to function as documented is to clear VM_MAYWRITE when mapping read-only. It turns out this functionality already exists for F_SEAL_FUTURE_WRITE - we can therefore simply adapt this logic to do the same for F_SEAL_WRITE. We then hit a chicken and egg situation in mmap_region() where the check for VM_MAYWRITE occurs before we are able to clear this flag. To work around this, perform this check after we invoke call_mmap(), with careful consideration of error paths. Thanks to Andy Lutomirski for the suggestion! [1]:https://lore.kernel.org/all/20230324133646.16101dfa666f253c4715d965@linux-foundation.org/ [2]:https://bugzilla.kernel.org/show_bug.cgi?id=217238 This patch (of 3): There is a general assumption that VMAs with the VM_SHARED flag set are writable. If the VM_MAYWRITE flag is not set, then this is simply not the case. Update those checks which affect the struct address_space->i_mmap_writable field to explicitly test for this by introducing [vma_]is_shared_maywrite() helper functions. This remains entirely conservative, as the lack of VM_MAYWRITE guarantees that the VMA cannot be written to. Link: https://lkml.kernel.org/r/cover.1697116581.git.lstoakes@gmail.com Link: https://lkml.kernel.org/r/d978aefefa83ec42d18dfa964ad180dbcde34795.1697116581.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> Suggested-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: stable@vger.kernel.org [isaacmanjarres: resolved merge conflicts due to due to refactoring that happened in upstream commit 5de195060b2e ("mm: resolve faulty mmap_region() error path behaviour")] Signed-off-by: Isaac J. Manjarres <isaacmanjarres@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-04kernel/fork: only call untrack_pfn_clear() on VMAs duplicated for fork()David Hildenbrand1-4/+5
[ Upstream commit e9f180d7cfde23b9f8eebd60272465176373ab2c ] Not intuitive, but vm_area_dup() located in kernel/fork.c is not only used for duplicating VMAs during fork(), but also for duplicating VMAs when splitting VMAs or when mremap()'ing them. VM_PFNMAP mappings can at least get ordinarily mremap()'ed (no change in size) and apparently also shrunk during mremap(), which implies duplicating the VMA in __split_vma() first. In case of ordinary mremap() (no change in size), we first duplicate the VMA in copy_vma_and_data()->copy_vma() to then call untrack_pfn_clear() on the old VMA: we effectively move the VM_PAT reservation. So the untrack_pfn_clear() call on the new VMA duplicating is wrong in that context. Splitting of VMAs seems problematic, because we don't duplicate/adjust the reservation when splitting the VMA. Instead, in memtype_erase() -- called during zapping/munmap -- we shrink a reservation in case only the end address matches: Assume we split a VMA into A and B, both would share a reservation until B is unmapped. So when unmapping B, the reservation would be updated to cover only A. When unmapping A, we would properly remove the now-shrunk reservation. That scenario describes the mremap() shrinking (old_size > new_size), where we split + unmap B, and the untrack_pfn_clear() on the new VMA when is wrong. What if we manage to split a VM_PFNMAP VMA into A and B and unmap A first? It would be broken because we would never free the reservation. Likely, there are ways to trigger such a VMA split outside of mremap(). Affecting other VMA duplication was not intended, vm_area_dup() being used outside of kernel/fork.c was an oversight. So let's fix that for; how to handle VMA splits better should be investigated separately. With a simple reproducer that uses mprotect() to split such a VMA I can trigger x86/PAT: pat_mremap:26448 freeing invalid memtype [mem 0x00000000-0x00000fff] Link: https://lkml.kernel.org/r/20250422144942.2871395-1-david@redhat.com Fixes: dc84bc2aba85 ("x86/mm/pat: Fix VM_PAT handling when fork() fails in copy_page_range()") Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Rik van Riel <riel@surriel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-10x86/mm/pat: Fix VM_PAT handling when fork() fails in copy_page_range()David Hildenbrand1-0/+4
[ Upstream commit dc84bc2aba85a1508f04a936f9f9a15f64ebfb31 ] If track_pfn_copy() fails, we already added the dst VMA to the maple tree. As fork() fails, we'll cleanup the maple tree, and stumble over the dst VMA for which we neither performed any reservation nor copied any page tables. Consequently untrack_pfn() will see VM_PAT and try obtaining the PAT information from the page table -- which fails because the page table was not copied. The easiest fix would be to simply clear the VM_PAT flag of the dst VMA if track_pfn_copy() fails. However, the whole thing is about "simply" clearing the VM_PAT flag is shaky as well: if we passed track_pfn_copy() and performed a reservation, but copying the page tables fails, we'll simply clear the VM_PAT flag, not properly undoing the reservation ... which is also wrong. So let's fix it properly: set the VM_PAT flag only if the reservation succeeded (leaving it clear initially), and undo the reservation if anything goes wrong while copying the page tables: clearing the VM_PAT flag after undoing the reservation. Note that any copied page table entries will get zapped when the VMA will get removed later, after copy_page_range() succeeded; as VM_PAT is not set then, we won't try cleaning VM_PAT up once more and untrack_pfn() will be happy. Note that leaving these page tables in place without a reservation is not a problem, as we are aborting fork(); this process will never run. A reproducer can trigger this usually at the first try: https://gitlab.com/davidhildenbrand/scratchspace/-/raw/main/reproducers/pat_fork.c WARNING: CPU: 26 PID: 11650 at arch/x86/mm/pat/memtype.c:983 get_pat_info+0xf6/0x110 Modules linked in: ... CPU: 26 UID: 0 PID: 11650 Comm: repro3 Not tainted 6.12.0-rc5+ #92 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-2.fc40 04/01/2014 RIP: 0010:get_pat_info+0xf6/0x110 ... Call Trace: <TASK> ... untrack_pfn+0x52/0x110 unmap_single_vma+0xa6/0xe0 unmap_vmas+0x105/0x1f0 exit_mmap+0xf6/0x460 __mmput+0x4b/0x120 copy_process+0x1bf6/0x2aa0 kernel_clone+0xab/0x440 __do_sys_clone+0x66/0x90 do_syscall_64+0x95/0x180 Likely this case was missed in: d155df53f310 ("x86/mm/pat: clear VM_PAT if copy_p4d_range failed") ... and instead of undoing the reservation we simply cleared the VM_PAT flag. Keep the documentation of these functions in include/linux/pgtable.h, one place is more than sufficient -- we should clean that up for the other functions like track_pfn_remap/untrack_pfn separately. Fixes: d155df53f310 ("x86/mm/pat: clear VM_PAT if copy_p4d_range failed") Fixes: 2ab640379a0a ("x86: PAT: hooks in generic vm code to help archs to track pfnmap regions - v3") Reported-by: xingwei lee <xrivendell7@gmail.com> Reported-by: yuxin wang <wang1315768607@163.com> Reported-by: Marius Fleischer <fleischermarius@gmail.com> Signed-off-by: David Hildenbrand <david@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: linux-mm@kvack.org Link: https://lore.kernel.org/r/20250321112323.153741-1-david@redhat.com Closes: https://lore.kernel.org/lkml/CABOYnLx_dnqzpCW99G81DmOr+2UzdmZMk=T3uxwNxwz+R1RAwg@mail.gmail.com/ Closes: https://lore.kernel.org/lkml/CAJg=8jwijTP5fre8woS4JVJQ8iUA6v+iNcsOgtj9Zfpc3obDOQ@mail.gmail.com/ Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-11-14posix-cpu-timers: Clear TICK_DEP_BIT_POSIX_TIMER on cloneBenjamin Segall1-0/+2
[ Upstream commit b5413156bad91dc2995a5c4eab1b05e56914638a ] When cloning a new thread, its posix_cputimers are not inherited, and are cleared by posix_cputimers_init(). However, this does not clear the tick dependency it creates in tsk->tick_dep_mask, and the handler does not reach the code to clear the dependency if there were no timers to begin with. Thus if a thread has a cputimer running before clone/fork, all descendants will prevent nohz_full unless they create a cputimer of their own. Fix this by entirely clearing the tick_dep_mask in copy_process(). (There is currently no inherited state that needs a tick dependency) Process-wide timers do not have this problem because fork does not copy signal_struct as a baseline, it creates one from scratch. Fixes: b78783000d5c ("posix-cpu-timers: Migrate to use new tick dependency mask model") Signed-off-by: Ben Segall <bsegall@google.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/all/xm26o737bq8o.fsf@google.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-11-08rcu-tasks: Initialize data to eliminate RCU-tasks/do_exit() deadlocksPaul E. McKenney1-0/+1
[ Upstream commit 46faf9d8e1d52e4a91c382c6c72da6bd8e68297b ] Holding a mutex across synchronize_rcu_tasks() and acquiring that same mutex in code called from do_exit() after its call to exit_tasks_rcu_start() but before its call to exit_tasks_rcu_stop() results in deadlock. This is by design, because tasks that are far enough into do_exit() are no longer present on the tasks list, making it a bit difficult for RCU Tasks to find them, let alone wait on them to do a voluntary context switch. However, such deadlocks are becoming more frequent. In addition, lockdep currently does not detect such deadlocks and they can be difficult to reproduce. In addition, if a task voluntarily context switches during that time (for example, if it blocks acquiring a mutex), then this task is in an RCU Tasks quiescent state. And with some adjustments, RCU Tasks could just as well take advantage of that fact. This commit therefore initializes the data structures that will be needed to rely on these quiescent states and to eliminate these deadlocks. Link: https://lore.kernel.org/all/20240118021842.290665-1-chenzhongjin@huawei.com/ Reported-by: Chen Zhongjin <chenzhongjin@huawei.com> Reported-by: Yang Jihong <yangjihong1@huawei.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Tested-by: Yang Jihong <yangjihong1@huawei.com> Tested-by: Chen Zhongjin <chenzhongjin@huawei.com> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Stable-dep-of: fd70e9f1d85f ("rcu-tasks: Fix access non-existent percpu rtpcp variable in rcu_tasks_need_gpcb()") Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-10-10close_range(): fix the logics in descriptor table trimmingAl Viro1-18/+14
commit 678379e1d4f7443b170939525d3312cfc37bf86b upstream. Cloning a descriptor table picks the size that would cover all currently opened files. That's fine for clone() and unshare(), but for close_range() there's an additional twist - we clone before we close, and it would be a shame to have close_range(3, ~0U, CLOSE_RANGE_UNSHARE) leave us with a huge descriptor table when we are not going to keep anything past stderr, just because some large file descriptor used to be open before our call has taken it out. Unfortunately, it had been dealt with in an inherently racy way - sane_fdtable_size() gets a "don't copy anything past that" argument (passed via unshare_fd() and dup_fd()), close_range() decides how much should be trimmed and passes that to unshare_fd(). The problem is, a range that used to extend to the end of descriptor table back when close_range() had looked at it might very well have stuff grown after it by the time dup_fd() has allocated a new files_struct and started to figure out the capacity of fdtable to be attached to that. That leads to interesting pathological cases; at the very least it's a QoI issue, since unshare(CLONE_FILES) is atomic in a sense that it takes a snapshot of descriptor table one might have observed at some point. Since CLOSE_RANGE_UNSHARE close_range() is supposed to be a combination of unshare(CLONE_FILES) with plain close_range(), ending up with a weird state that would never occur with unshare(2) is confusing, to put it mildly. It's not hard to get rid of - all it takes is passing both ends of the range down to sane_fdtable_size(). There we are under ->files_lock, so the race is trivially avoided. So we do the following: * switch close_files() from calling unshare_fd() to calling dup_fd(). * undo the calling convention change done to unshare_fd() in 60997c3d45d9 "close_range: add CLOSE_RANGE_UNSHARE" * introduce struct fd_range, pass a pointer to that to dup_fd() and sane_fdtable_size() instead of "trim everything past that point" they are currently getting. NULL means "we are not going to be punching any holes"; NR_OPEN_MAX is gone. * make sane_fdtable_size() use find_last_bit() instead of open-coding it; it's easier to follow that way. * while we are at it, have dup_fd() report errors by returning ERR_PTR(), no need to use a separate int *errorp argument. Fixes: 60997c3d45d9 "close_range: add CLOSE_RANGE_UNSHARE" Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-21Revert "fork: defer linking file vma until vma is fully initialized"Sam James1-9/+9
This reverts commit cec11fa2eb512ebe3a459c185f4aca1d44059bbf which is commit 35e351780fa9d8240dd6f7e4f245f9ea37e96c19 upstream. The backport is incomplete and causes xfstests failures. The consequences of the incomplete backport seem worse than the original issue, so pick the lesser evil and revert until a full backport is ready. Link: https://lore.kernel.org/stable/20240604004751.3883227-1-leah.rumancik@gmail.com/ Reported-by: Leah Rumancik <leah.rumancik@gmail.com> Signed-off-by: Sam James <sam@gentoo.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-05-02fork: defer linking file vma until vma is fully initializedMiaohe Lin1-9/+9
commit 35e351780fa9d8240dd6f7e4f245f9ea37e96c19 upstream. Thorvald reported a WARNING [1]. And the root cause is below race: CPU 1 CPU 2 fork hugetlbfs_fallocate dup_mmap hugetlbfs_punch_hole i_mmap_lock_write(mapping); vma_interval_tree_insert_after -- Child vma is visible through i_mmap tree. i_mmap_unlock_write(mapping); hugetlb_dup_vma_private -- Clear vma_lock outside i_mmap_rwsem! i_mmap_lock_write(mapping); hugetlb_vmdelete_list vma_interval_tree_foreach hugetlb_vma_trylock_write -- Vma_lock is cleared. tmp->vm_ops->open -- Alloc new vma_lock outside i_mmap_rwsem! hugetlb_vma_unlock_write -- Vma_lock is assigned!!! i_mmap_unlock_write(mapping); hugetlb_dup_vma_private() and hugetlb_vm_op_open() are called outside i_mmap_rwsem lock while vma lock can be used in the same time. Fix this by deferring linking file vma until vma is fully initialized. Those vmas should be initialized first before they can be used. Link: https://lkml.kernel.org/r/20240410091441.3539905-1-linmiaohe@huawei.com Fixes: 8d9bfb260814 ("hugetlb: add vma based lock for pmd sharing") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reported-by: Thorvald Natvig <thorvald@google.com> Closes: https://lore.kernel.org/linux-mm/20240129161735.6gmjsswx62o4pbja@revolver/T/ [1] Reviewed-by: Jane Chu <jane.chu@oracle.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Mateusz Guzik <mjguzik@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Cc: Tycho Andersen <tandersen@netflix.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-12-03mm: add a NO_INHERIT flag to the PR_SET_MDWE prctlFlorent Revest1-1/+1
[ Upstream commit 24e41bf8a6b424c76c5902fb999e9eca61bdf83d ] This extends the current PR_SET_MDWE prctl arg with a bit to indicate that the process doesn't want MDWE protection to propagate to children. To implement this no-inherit mode, the tag in current->mm->flags must be absent from MMF_INIT_MASK. This means that the encoding for "MDWE but without inherit" is different in the prctl than in the mm flags. This leads to a bit of bit-mangling in the prctl implementation. Link: https://lkml.kernel.org/r/20230828150858.393570-6-revest@chromium.org Signed-off-by: Florent Revest <revest@chromium.org> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Alexey Izbyshev <izbyshev@ispras.ru> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Ayush Jain <ayush.jain3@amd.com> Cc: David Hildenbrand <david@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: Joey Gouly <joey.gouly@arm.com> Cc: KP Singh <kpsingh@kernel.org> Cc: Mark Brown <broonie@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Peter Xu <peterx@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Szabolcs Nagy <Szabolcs.Nagy@arm.com> Cc: Topi Miettinen <toiwoton@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Stable-dep-of: 793838138c15 ("prctl: Disable prctl(PR_SET_MDWE) on parisc") Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-09-01Merge tag 'percpu-for-6.6' of ↵Linus Torvalds1-11/+4
git://git.kernel.org/pub/scm/linux/kernel/git/dennis/percpu Pull percpu updates from Dennis Zhou: "One bigger change to percpu_counter's api allowing for init and destroy of multiple counters via percpu_counter_init_many() and percpu_counter_destroy_many(). This is used to help begin remediating a performance regression with percpu rss stats. Additionally, it seems larger core count machines are feeling the burden of the single threaded allocation of percpu. Mateusz is thinking about it and I will spend some time on it too. percpu: - A couple cleanups by Baoquan He and Bibo Mao. The only behavior change is to start printing messages if we're under the warn limit for failed atomic allocations. percpu_counter: - Shakeel introduced percpu counters into mm_struct which caused percpu allocations be on the hot path [1]. Originally I spent some time trying to improve the percpu allocator, but instead preferred what Mateusz Guzik proposed grouping at the allocation site, percpu_counter_init_many(). This allows a single percpu allocation to be shared by the counters. I like this approach because it creates a shared lifetime by the allocations. Additionally, I believe many inits have higher level synchronization requirements, like percpu_counter does against HOTPLUG_CPU. Therefore we can group these optimizations together" Link: https://lore.kernel.org/linux-mm/20221024052841.3291983-1-shakeelb@google.com/ [1] * tag 'percpu-for-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/dennis/percpu: kernel/fork: group allocation/free of per-cpu counters for mm struct pcpcntr: add group allocation/free mm/percpu.c: print error message too if atomic alloc failed mm/percpu.c: optimize the code in pcpu_setup_first_chunk() a little bit mm/percpu.c: remove redundant check mm/percpu: Remove some local variables in pcpu_populate_pte
2023-08-29Merge tag 'mm-nonmm-stable-2023-08-28-22-48' of ↵Linus Torvalds1-13/+9
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 ...
2023-08-25kernel/fork: group allocation/free of per-cpu counters for mm structMateusz Guzik1-11/+4
A trivial execve scalability test which tries to be very friendly (statically linked binaries, all separate) is predominantly bottlenecked by back-to-back per-cpu counter allocations which serialize on global locks. Ease the pain by allocating and freeing them in one go. Bench can be found here: http://apollo.backplane.com/DFlyMisc/doexec.c $ cc -static -O2 -o static-doexec doexec.c $ ./static-doexec $(nproc) Even at a very modest scale of 26 cores (ops/s): before: 133543.63 after: 186061.81 (+39%) While with the patch these allocations remain a significant problem, the primary bottleneck shifts to page release handling. Signed-off-by: Mateusz Guzik <mjguzik@gmail.com> Link: https://lore.kernel.org/r/20230823050609.2228718-3-mjguzik@gmail.com [Dennis: reflowed 1 line] Signed-off-by: Dennis Zhou <dennis@kernel.org>
2023-08-21kernel/fork: stop playing lockless games for exe_file replacementMateusz Guzik1-13/+9
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>
2023-07-13kernel/fork: beware of __put_task_struct() calling contextWander Lairson Costa1-0/+8
Under PREEMPT_RT, __put_task_struct() indirectly acquires sleeping locks. Therefore, it can't be called from an non-preemptible context. One practical example is splat inside inactive_task_timer(), which is called in a interrupt context: CPU: 1 PID: 2848 Comm: life Kdump: loaded Tainted: G W --------- Hardware name: HP ProLiant DL388p Gen8, BIOS P70 07/15/2012 Call Trace: dump_stack_lvl+0x57/0x7d mark_lock_irq.cold+0x33/0xba mark_lock+0x1e7/0x400 mark_usage+0x11d/0x140 __lock_acquire+0x30d/0x930 lock_acquire.part.0+0x9c/0x210 rt_spin_lock+0x27/0xe0 refill_obj_stock+0x3d/0x3a0 kmem_cache_free+0x357/0x560 inactive_task_timer+0x1ad/0x340 __run_hrtimer+0x8a/0x1a0 __hrtimer_run_queues+0x91/0x130 hrtimer_interrupt+0x10f/0x220 __sysvec_apic_timer_interrupt+0x7b/0xd0 sysvec_apic_timer_interrupt+0x4f/0xd0 asm_sysvec_apic_timer_interrupt+0x12/0x20 RIP: 0033:0x7fff196bf6f5 Instead of calling __put_task_struct() directly, we defer it using call_rcu(). A more natural approach would use a workqueue, but since in PREEMPT_RT, we can't allocate dynamic memory from atomic context, the code would become more complex because we would need to put the work_struct instance in the task_struct and initialize it when we allocate a new task_struct. The issue is reproducible with stress-ng: while true; do stress-ng --sched deadline --sched-period 1000000000 \ --sched-runtime 800000000 --sched-deadline \ 1000000000 --mmapfork 23 -t 20 done Reported-by: Hu Chunyu <chuhu@redhat.com> Suggested-by: Oleg Nesterov <oleg@redhat.com> Suggested-by: Valentin Schneider <vschneid@redhat.com> Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Wander Lairson Costa <wander@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20230614122323.37957-2-wander@redhat.com
2023-07-08fork: lock VMAs of the parent process when forkingSuren Baghdasaryan1-0/+1
When forking a child process, the parent write-protects anonymous pages and COW-shares them with the child being forked using copy_present_pte(). We must not take any concurrent page faults on the source vma's as they are being processed, as we expect both the vma and the pte's behind it to be stable. For example, the anon_vma_fork() expects the parents vma->anon_vma to not change during the vma copy. A concurrent page fault on a page newly marked read-only by the page copy might trigger wp_page_copy() and a anon_vma_prepare(vma) on the source vma, defeating the anon_vma_clone() that wasn't done because the parent vma originally didn't have an anon_vma, but we now might end up copying a pte entry for a page that has one. Before the per-vma lock based changes, the mmap_lock guaranteed exclusion with concurrent page faults. But now we need to do a vma_start_write() to make sure no concurrent faults happen on this vma while it is being processed. This fix can potentially regress some fork-heavy workloads. Kernel build time did not show noticeable regression on a 56-core machine while a stress test mapping 10000 VMAs and forking 5000 times in a tight loop shows ~5% regression. If such fork time regression is unacceptable, disabling CONFIG_PER_VMA_LOCK should restore its performance. Further optimizations are possible if this regression proves to be problematic. Suggested-by: David Hildenbrand <david@redhat.com> Reported-by: Jiri Slaby <jirislaby@kernel.org> Closes: https://lore.kernel.org/all/dbdef34c-3a07-5951-e1ae-e9c6e3cdf51b@kernel.org/ Reported-by: Holger Hoffstätte <holger@applied-asynchrony.com> Closes: https://lore.kernel.org/all/b198d649-f4bf-b971-31d0-e8433ec2a34c@applied-asynchrony.com/ Reported-by: Jacob Young <jacobly.alt@gmail.com> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217624 Fixes: 0bff0aaea03e ("x86/mm: try VMA lock-based page fault handling first") Cc: stable@vger.kernel.org Signed-off-by: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2023-06-28Merge tag 'mm-nonmm-stable-2023-06-24-19-23' of ↵Linus Torvalds1-7/+3
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull non-mm updates from Andrew Morton: - Arnd Bergmann has fixed a bunch of -Wmissing-prototypes in top-level directories - Douglas Anderson has added a new "buddy" mode to the hardlockup detector. It permits the detector to work on architectures which cannot provide the required interrupts, by having CPUs periodically perform checks on other CPUs - Zhen Lei has enhanced kexec's ability to support two crash regions - Petr Mladek has done a lot of cleanup on the hard lockup detector's Kconfig entries - And the usual bunch of singleton patches in various places * tag 'mm-nonmm-stable-2023-06-24-19-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (72 commits) kernel/time/posix-stubs.c: remove duplicated include ocfs2: remove redundant assignment to variable bit_off watchdog/hardlockup: fix typo in config HARDLOCKUP_DETECTOR_PREFER_BUDDY powerpc: move arch_trigger_cpumask_backtrace from nmi.h to irq.h devres: show which resource was invalid in __devm_ioremap_resource() watchdog/hardlockup: define HARDLOCKUP_DETECTOR_ARCH watchdog/sparc64: define HARDLOCKUP_DETECTOR_SPARC64 watchdog/hardlockup: make HAVE_NMI_WATCHDOG sparc64-specific watchdog/hardlockup: declare arch_touch_nmi_watchdog() only in linux/nmi.h watchdog/hardlockup: make the config checks more straightforward watchdog/hardlockup: sort hardlockup detector related config values a logical way watchdog/hardlockup: move SMP barriers from common code to buddy code watchdog/buddy: simplify the dependency for HARDLOCKUP_DETECTOR_PREFER_BUDDY watchdog/buddy: don't copy the cpumask in watchdog_next_cpu() watchdog/buddy: cleanup how watchdog_buddy_check_hardlockup() is called watchdog/hardlockup: remove softlockup comment in touch_nmi_watchdog() watchdog/hardlockup: in watchdog_hardlockup_check() use cpumask_copy() watchdog/hardlockup: don't use raw_cpu_ptr() in watchdog_hardlockup_kick() watchdog/hardlockup: HAVE_NMI_WATCHDOG must implement watchdog_hardlockup_probe() watchdog/hardlockup: keep kernel.nmi_watchdog sysctl as 0444 if probe fails ...
2023-06-09fork: optimize memcg_charge_kernel_stack() a bitHaifeng Xu1-7/+3
Since commit f1c1a9ee00e4 ("fork: Move memcg_charge_kernel_stack() into CONFIG_VMAP_STACK"), memcg_charge_kernel_stack() has been moved into CONFIG_VMAP_STACK block, so the CONFIG_VMAP_STACK check can be removed. Furthermore, memcg_charge_kernel_stack() is only invoked by alloc_thread_stack_node() instead of dup_task_struct(). If memcg_kmem_charge_page() fails, the uncharge process is handled in memcg_charge_kernel_stack() itself instead of free_thread_stack(), so remove the incorrect comments. If memcg_charge_kernel_stack() fails to charge pages used by kernel stack, only charged pages need to be uncharged. It's unnecessary to uncharge those pages which memory cgroup pointer is NULL. [akpm@linux-foundation.org: remove assertion that PAGE_SIZE is a multiple of 1k] Link: https://lkml.kernel.org/r/20230508064458.32855-1-haifeng.xu@shopee.com Signed-off-by: Haifeng Xu <haifeng.xu@shopee.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-06-07Merge tag 'for-netdev' of ↵Jakub Kicinski1-1/+1
https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf Daniel Borkmann says: ==================== pull-request: bpf 2023-06-07 We've added 7 non-merge commits during the last 7 day(s) which contain a total of 12 files changed, 112 insertions(+), 7 deletions(-). The main changes are: 1) Fix a use-after-free in BPF's task local storage, from KP Singh. 2) Make struct path handling more robust in bpf_d_path, from Jiri Olsa. 3) Fix a syzbot NULL-pointer dereference in sockmap, from Eric Dumazet. 4) UAPI fix for BPF_NETFILTER before final kernel ships, from Florian Westphal. 5) Fix map-in-map array_map_gen_lookup code generation where elem_size was not being set for inner maps, from Rhys Rustad-Elliott. 6) Fix sockopt_sk selftest's NETLINK_LIST_MEMBERSHIPS assertion, from Yonghong Song. * tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf: bpf: Add extra path pointer check to d_path helper selftests/bpf: Fix sockopt_sk selftest bpf: netfilter: Add BPF_NETFILTER bpf_attach_type selftests/bpf: Add access_inner_map selftest bpf: Fix elem_size not being set for inner maps bpf: Fix UAF in task local storage bpf, sockmap: Avoid potential NULL dereference in sk_psock_verdict_data_ready() ==================== Link: https://lore.kernel.org/r/20230607220514.29698-1-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-06-02bpf: Fix UAF in task local storageKP Singh1-1/+1
When task local storage was generalized for tracing programs, the bpf_task_local_storage callback was moved from a BPF LSM hook callback for security_task_free LSM hook to it's own callback. But a failure case in bad_fork_cleanup_security was missed which, when triggered, led to a dangling task owner pointer and a subsequent use-after-free. Move the bpf_task_storage_free to the very end of free_task to handle all failure cases. This issue was noticed when a BPF LSM program was attached to the task_alloc hook on a kernel with KASAN enabled. The program used bpf_task_storage_get to copy the task local storage from the current task to the new task being created. Fixes: a10787e6d58c ("bpf: Enable task local storage for tracing programs") Reported-by: Kuba Piecuch <jpiecuch@google.com> Signed-off-by: KP Singh <kpsingh@kernel.org> Acked-by: Song Liu <song@kernel.org> Link: https://lore.kernel.org/r/20230602002612.1117381-1-kpsingh@kernel.org Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2023-06-01fork, vhost: Use CLONE_THREAD to fix freezer/ps regressionMike Christie1-8/+5
When switching from kthreads to vhost_tasks two bugs were added: 1. The vhost worker tasks's now show up as processes so scripts doing ps or ps a would not incorrectly detect the vhost task as another process. 2. kthreads disabled freeze by setting PF_NOFREEZE, but vhost tasks's didn't disable or add support for them. To fix both bugs, this switches the vhost task to be thread in the process that does the VHOST_SET_OWNER ioctl, and has vhost_worker call get_signal to support SIGKILL/SIGSTOP and freeze signals. Note that SIGKILL/STOP support is required because CLONE_THREAD requires CLONE_SIGHAND which requires those 2 signals to be supported. This is a modified version of the patch written by Mike Christie <michael.christie@oracle.com> which was a modified version of patch originally written by Linus. Much of what depended upon PF_IO_WORKER now depends on PF_USER_WORKER. Including ignoring signals, setting up the register state, and having get_signal return instead of calling do_group_exit. Tidied up the vhost_task abstraction so that the definition of vhost_task only needs to be visible inside of vhost_task.c. Making it easier to review the code and tell what needs to be done where. As part of this the main loop has been moved from vhost_worker into vhost_task_fn. vhost_worker now returns true if work was done. The main loop has been updated to call get_signal which handles SIGSTOP, freezing, and collects the message that tells the thread to exit as part of process exit. This collection clears __fatal_signal_pending. This collection is not guaranteed to clear signal_pending() so clear that explicitly so the schedule() sleeps. For now the vhost thread continues to exist and run work until the last file descriptor is closed and the release function is called as part of freeing struct file. To avoid hangs in the coredump rendezvous and when killing threads in a multi-threaded exec. The coredump code and de_thread have been modified to ignore vhost threads. Remvoing the special case for exec appears to require teaching vhost_dev_flush how to directly complete transactions in case the vhost thread is no longer running. Removing the special case for coredump rendezvous requires either the above fix needed for exec or moving the coredump rendezvous into get_signal. Fixes: 6e890c5d5021 ("vhost: use vhost_tasks for worker threads") Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Co-developed-by: Mike Christie <michael.christie@oracle.com> Signed-off-by: Mike Christie <michael.christie@oracle.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2023-04-30Merge tag 'iommu-updates-v6.4' of ↵Linus Torvalds1-0/+1
git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu Pull iommu updates from Joerg Roedel: - Convert to platform remove callback returning void - Extend changing default domain to normal group - Intel VT-d updates: - Remove VT-d virtual command interface and IOASID - Allow the VT-d driver to support non-PRI IOPF - Remove PASID supervisor request support - Various small and misc cleanups - ARM SMMU updates: - Device-tree binding updates: * Allow Qualcomm GPU SMMUs to accept relevant clock properties * Document Qualcomm 8550 SoC as implementing an MMU-500 * Favour new "qcom,smmu-500" binding for Adreno SMMUs - Fix S2CR quirk detection on non-architectural Qualcomm SMMU implementations - Acknowledge SMMUv3 PRI queue overflow when consuming events - Document (in a comment) why ATS is disabled for bypass streams - AMD IOMMU updates: - 5-level page-table support - NUMA awareness for memory allocations - Unisoc driver: Support for reattaching an existing domain - Rockchip driver: Add missing set_platform_dma_ops callback - Mediatek driver: Adjust the dma-ranges - Various other small fixes and cleanups * tag 'iommu-updates-v6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu: (82 commits) iommu: Remove iommu_group_get_by_id() iommu: Make iommu_release_device() static iommu/vt-d: Remove BUG_ON in dmar_insert_dev_scope() iommu/vt-d: Remove a useless BUG_ON(dev->is_virtfn) iommu/vt-d: Remove BUG_ON in map/unmap() iommu/vt-d: Remove BUG_ON when domain->pgd is NULL iommu/vt-d: Remove BUG_ON in handling iotlb cache invalidation iommu/vt-d: Remove BUG_ON on checking valid pfn range iommu/vt-d: Make size of operands same in bitwise operations iommu/vt-d: Remove PASID supervisor request support iommu/vt-d: Use non-privileged mode for all PASIDs iommu/vt-d: Remove extern from function prototypes iommu/vt-d: Do not use GFP_ATOMIC when not needed iommu/vt-d: Remove unnecessary checks in iopf disabling path iommu/vt-d: Move PRI handling to IOPF feature path iommu/vt-d: Move pfsid and ats_qdep calculation to device probe path iommu/vt-d: Move iopf code from SVA to IOPF enabling path iommu/vt-d: Allow SVA with device-specific IOPF dmaengine: idxd: Add enable/disable device IOPF feature arm64: dts: mt8186: Add dma-ranges for the parent "soc" node ...
2023-04-28Merge tag 'trace-v6.4' of ↵Linus Torvalds1-0/+2
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing updates from Steven Rostedt: - User events are finally ready! After lots of collaboration between various parties, we finally locked down on a stable interface for user events that can also work with user space only tracing. This is implemented by telling the kernel (or user space library, but that part is user space only and not part of this patch set), where the variable is that the application uses to know if something is listening to the trace. There's also an interface to tell the kernel about these events, which will show up in the /sys/kernel/tracing/events/user_events/ directory, where it can be enabled. When it's enabled, the kernel will update the variable, to tell the application to start writing to the kernel. See https://lwn.net/Articles/927595/ - Cleaned up the direct trampolines code to simplify arm64 addition of direct trampolines. Direct trampolines use the ftrace interface but instead of jumping to the ftrace trampoline, applications (mostly BPF) can register their own trampoline for performance reasons. - Some updates to the fprobe infrastructure. fprobes are more efficient than kprobes, as it does not need to save all the registers that kprobes on ftrace do. More work needs to be done before the fprobes will be exposed as dynamic events. - More updates to references to the obsolete path of /sys/kernel/debug/tracing for the new /sys/kernel/tracing path. - Add a seq_buf_do_printk() helper to seq_bufs, to print a large buffer line by line instead of all at once. There are users in production kernels that have a large data dump that originally used printk() directly, but the data dump was larger than what printk() allowed as a single print. Using seq_buf() to do the printing fixes that. - Add /sys/kernel/tracing/touched_functions that shows all functions that was every traced by ftrace or a direct trampoline. This is used for debugging issues where a traced function could have caused a crash by a bpf program or live patching. - Add a "fields" option that is similar to "raw" but outputs the fields of the events. It's easier to read by humans. - Some minor fixes and clean ups. * tag 'trace-v6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (41 commits) ring-buffer: Sync IRQ works before buffer destruction tracing: Add missing spaces in trace_print_hex_seq() ring-buffer: Ensure proper resetting of atomic variables in ring_buffer_reset_online_cpus recordmcount: Fix memory leaks in the uwrite function tracing/user_events: Limit max fault-in attempts tracing/user_events: Prevent same address and bit per process tracing/user_events: Ensure bit is cleared on unregister tracing/user_events: Ensure write index cannot be negative seq_buf: Add seq_buf_do_printk() helper tracing: Fix print_fields() for __dyn_loc/__rel_loc tracing/user_events: Set event filter_type from type ring-buffer: Clearly check null ptr returned by rb_set_head_page() tracing: Unbreak user events tracing/user_events: Use print_format_fields() for trace output tracing/user_events: Align structs with tabs for readability tracing/user_events: Limit global user_event count tracing/user_events: Charge event allocs to cgroups tracing/user_events: Update documentation for ABI tracing/user_events: Use write ABI in example tracing/user_events: Add ABI self-test ...
2023-04-28Merge tag 'sched-core-2023-04-27' of ↵Linus Torvalds1-1/+8
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler updates from Ingo Molnar: - Allow unprivileged PSI poll()ing - Fix performance regression introduced by mm_cid - Improve livepatch stalls by adding livepatch task switching to cond_resched(). This resolves livepatching busy-loop stalls with certain CPU-bound kthreads - Improve sched_move_task() performance on autogroup configs - On core-scheduling CPUs, avoid selecting throttled tasks to run - Misc cleanups, fixes and improvements * tag 'sched-core-2023-04-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/clock: Fix local_clock() before sched_clock_init() sched/rt: Fix bad task migration for rt