user/sven/linux.git/init/init_task.c, branch v6.7.9

Merge tag 'mm-nonmm-stable-2023-11-02-14-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2023-11-03T06:53:31Z

Pull non-MM updates from Andrew Morton: "As usual, lots of singleton and doubleton patches all over the tree and there's little I can say which isn't in the individual changelogs. The lengthier patch series are - 'kdump: use generic functions to simplify crashkernel reservation in arch', from Baoquan He. This is mainly cleanups and consolidation of the 'crashkernel=' kernel parameter handling - After much discussion, David Laight's 'minmax: Relax type checks in min() and max()' is here. Hopefully reduces some typecasting and the use of min_t() and max_t() - A group of patches from Oleg Nesterov which clean up and slightly fix our handling of reads from /proc/PID/task/... and which remove task_struct.thread_group" * tag 'mm-nonmm-stable-2023-11-02-14-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (64 commits) scripts/gdb/vmalloc: disable on no-MMU scripts/gdb: fix usage of MOD_TEXT not defined when CONFIG_MODULES=n .mailmap: add address mapping for Tomeu Vizoso mailmap: update email address for Claudiu Beznea tools/testing/selftests/mm/run_vmtests.sh: lower the ptrace permissions .mailmap: map Benjamin Poirier's address scripts/gdb: add lx_current support for riscv ocfs2: fix a spelling typo in comment proc: test ProtectionKey in proc-empty-vm test proc: fix proc-empty-vm test with vsyscall fs/proc/base.c: remove unneeded semicolon do_io_accounting: use sig->stats_lock do_io_accounting: use __for_each_thread() ocfs2: replace BUG_ON() at ocfs2_num_free_extents() with ocfs2_error() ocfs2: fix a typo in a comment scripts/show_delta: add __main__ judgement before main code treewide: mark stuff as __ro_after_init fs: ocfs2: check status values proc: test /proc/${pid}/statm compiler.h: move __is_constexpr() to compiler.h ...

kill task_struct->thread_group

2023-10-04T17:41:56Z

The last user was removed by the previous patch. Link: https://lkml.kernel.org/r/20230826111409.GA23243@redhat.com Signed-off-by: Oleg Nesterov Cc: Eric W. Biederman Cc: Peter Zijlstra Signed-off-by: Andrew Morton

sched: Add task_struct->faults_disabled_mapping

2023-09-12T03:59:46Z

There has been a long standing page cache coherence bug with direct IO. This provides part of a mechanism to fix it, currently just used by bcachefs but potentially worth promoting to the VFS. Direct IO evicts the range of the pagecache being read or written to. For reads, we need dirty pages to be written to disk, so that the read doesn't return stale data. For writes, we need to evict that range of the pagecache so that it's not stale after the write completes. However, without a locking mechanism to prevent those pages from being re-added to the pagecache - by a buffered read or page fault - page cache inconsistency is still possible. This isn't necessarily just an issue for userspace when they're playing games; filesystems may hang arbitrary state off the pagecache, and so page cache inconsistency may cause real filesystem bugs, depending on the filesystem. This is less of an issue for iomap based filesystems, but e.g. buffer heads caches disk block mappings (!) and attaches them to the pagecache, and bcachefs attaches disk reservations to pagecache pages. This issue has been hard to fix, because - we need to add a lock (henceforth called pagecache_add_lock), which would be held for the duration of the direct IO - page faults add pages to the page cache, thus need to take the same lock - dio -> gup -> page fault thus can deadlock And we cannot enforce a lock ordering with this lock, since userspace will be controlling the lock ordering (via the fd and buffer arguments to direct IOs), so we need a different method of deadlock avoidance. We need to tell the page fault handler that we're already holding a pagecache_add_lock, and since plumbing it through the entire gup() path would be highly impractical this adds a field to task_struct. Then the full method is: - in the dio path, when we first take the pagecache_add_lock, note the mapping in the current task_struct - in the page fault handler, if faults_disabled_mapping is set, we check if it's the same mapping as the one we're taking a page fault for, and if so return an error. Then we check lock ordering: if there's a lock ordering violation and trylock fails, we'll have to cycle the locks and return an error that tells the DIO path to retry: faults_disabled_mapping is also used for signalling "locks were dropped, please retry". Also relevant to this patch: mapping->invalidate_lock. mapping->invalidate_lock provides most of the required semantics - it's used by truncate/fallocate to block pages being added to the pagecache. However, since it's a rwsem, direct IOs would need to take the write side in order to block page cache adds, and would then be exclusive with each other - we'll need a new type of lock to pair with this approach. Signed-off-by: Kent Overstreet Cc: Jan Kara Cc: Darrick J. Wong Cc: linux-fsdevel@vger.kernel.org Cc: Andreas Grünbacher

rcu-tasks: Add data structures for lightweight grace periods

2022-06-20T16:22:28Z

This commit adds fields to task_struct and to rcu_tasks_percpu that will be used to avoid the task-list scan for RCU Tasks Trace grace periods, and also initializes these fields. Signed-off-by: Paul E. McKenney Cc: Neeraj Upadhyay Cc: Eric Dumazet Cc: Alexei Starovoitov Cc: Andrii Nakryiko Cc: Martin KaFai Lau Cc: KP Singh

kcsan: Remove redundant zero-initialization of globals

2021-12-10T00:42:26Z

They are implicitly zero-initialized, remove explicit initialization. It keeps the upcoming additions to kcsan_ctx consistent with the rest. No functional change intended. Signed-off-by: Marco Elver Acked-by: Mark Rutland Signed-off-by: Paul E. McKenney

sched: Introduce task_struct::user_cpus_ptr to track requested affinity

2021-08-20T10:33:00Z

In preparation for saving and restoring the user-requested CPU affinity mask of a task, add a new cpumask_t pointer to 'struct task_struct'. If the pointer is non-NULL, then the mask is copied across fork() and freed on task exit. Signed-off-by: Will Deacon Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Valentin Schneider Link: https://lore.kernel.org/r/20210730112443.23245-7-will@kernel.org

sched: Change task_struct::state

2021-06-18T09:43:09Z

Change the type and name of task_struct::state. Drop the volatile and shrink it to an 'unsigned int'. Rename it in order to find all uses such that we can use READ_ONCE/WRITE_ONCE as appropriate. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Daniel Bristot de Oliveira Acked-by: Will Deacon Acked-by: Daniel Thompson Link: https://lore.kernel.org/r/20210611082838.550736351@infradead.org

seccomp: Fix CONFIG tests for Seccomp_filters

2021-03-31T05:33:50Z

Strictly speaking, seccomp filters are only used when CONFIG_SECCOMP_FILTER. This patch fixes the condition to enable "Seccomp_filters" in /proc/$pid/status. Signed-off-by: Kenta Tada Fixes: c818c03b661c ("seccomp: Report number of loaded filters in /proc/$pid/status") Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/OSBPR01MB26772D245E2CF4F26B76A989F5669@OSBPR01MB2677.jpnprd01.prod.outlook.com

fgraph: Initialize tracing_graph_pause at task creation

2021-01-29T20:07:32Z

On some archs, the idle task can call into cpu_suspend(). The cpu_suspend() will disable or pause function graph tracing, as there's some paths in bringing down the CPU that can have issues with its return address being modified. The task_struct structure has a "tracing_graph_pause" atomic counter, that when set to something other than zero, the function graph tracer will not modify the return address. The problem is that the tracing_graph_pause counter is initialized when the function graph tracer is enabled. This can corrupt the counter for the idle task if it is suspended in these architectures. CPU 1 CPU 2 ----- ----- do_idle() cpu_suspend() pause_graph_tracing() task_struct->tracing_graph_pause++ (0 -> 1) start_graph_tracing() for_each_online_cpu(cpu) { ftrace_graph_init_idle_task(cpu) task-struct->tracing_graph_pause = 0 (1 -> 0) unpause_graph_tracing() task_struct->tracing_graph_pause-- (0 -> -1) The above should have gone from 1 to zero, and enabled function graph tracing again. But instead, it is set to -1, which keeps it disabled. There's no reason that the field tracing_graph_pause on the task_struct can not be initialized at boot up. Cc: stable@vger.kernel.org Fixes: 380c4b1411ccd ("tracing/function-graph-tracer: append the tracing_graph_flag") Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=211339 Reported-by: pierre.gondois@arm.com Signed-off-by: Steven Rostedt (VMware)

kasan, arm64: only use kasan_depth for software modes

2020-12-22T20:55:07Z

This is a preparatory commit for the upcoming addition of a new hardware tag-based (MTE-based) KASAN mode. Hardware tag-based KASAN won't use kasan_depth. Only define and use it when one of the software KASAN modes are enabled. No functional changes for software modes. Link: https://lkml.kernel.org/r/e16f15aeda90bc7fb4dfc2e243a14b74cc5c8219.1606161801.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Signed-off-by: Vincenzo Frascino Reviewed-by: Catalin Marinas Reviewed-by: Alexander Potapenko Tested-by: Vincenzo Frascino Cc: Andrey Ryabinin Cc: Branislav Rankov Cc: Dmitry Vyukov Cc: Evgenii Stepanov Cc: Kevin Brodsky Cc: Marco Elver Cc: Vasily Gorbik Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds