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| author | Thomas Gleixner <tglx@kernel.org> | 2026-08-17 10:29:52 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@kernel.org> | 2026-08-17 10:29:52 +0200 |
| commit | 0eaed89c18aeedf0898baf2dbf5ff027c6795152 (patch) | |
| tree | 4422cb10597581af05704ba6510018aabf25b268 /kernel/exec_state.c | |
| parent | c66494c79ede1af529dbf67f9ed6fdbf42e05ef3 (diff) | |
| parent | 8b4127f6db40381229f3564d34ac35f36311c201 (diff) | |
Merge tag 'timers-v7.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/daniel.lezcano/linux into timers/clocksource
- Use designated initializers for sh_mtu2, sh_cmt, and sh_tmu, and
drop the unused initializer in the platform_device_id table for
sh_mtu2 (Uwe Kleine-König)
- Remove redundant dev_err()/dev_err_probe() messages when
devm_request_*_irq() fails, as the helper already logs an error
message (Pan Chuang)
- Fix a boot hang on Allwinner D1 when a forced minimum delta is used
with the sun4i timer (Felix Yan)
- Fix an IRQ leak in the cpuhp_setup_state() error path by freeing the
IRQ on failure in the NXP PIT driver (WenTao Liang)
- Fix incorrect unmapping of shared MMIO between the clocksource and
clockevent drivers. If one of them fails to initialize, the error
path unmaps the shared MMIO region, leaving the other driver with an
invalid mapping on clps711x (Guangshuo Li)
- Make the samsung_pwm driver compatible with PREEMPT_RT by replacing
regular spinlocks with raw_spinlock_t in atomic contexts (Marek
Szyprowski)
- Use __raw_readl() and __raw_writel() instead of ioread32() and
iowrite32() to support SWAP_IO_SPACE in the rtl-otto driver (Rustam
Adilov)
- Fix a missing clk_disable_unprepare() call in the timer
initialization error path of the Armada driver (Yuho Choi)
Link: https://lore.kernel.org/lkml/75feea31-683d-45a1-87f4-ab045e0152ae@oss.qualcomm.com
Diffstat (limited to 'kernel/exec_state.c')
| -rw-r--r-- | kernel/exec_state.c | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/kernel/exec_state.c b/kernel/exec_state.c new file mode 100644 index 000000000000..6034f4b4808f --- /dev/null +++ b/kernel/exec_state.c @@ -0,0 +1,119 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2026 Christian Brauner <brauner@kernel.org> */ +#include <linux/init.h> +#include <linux/rcupdate.h> +#include <linux/refcount.h> +#include <linux/sched.h> +#include <linux/sched/coredump.h> +#include <linux/sched/exec_state.h> +#include <linux/sched/signal.h> +#include <linux/slab.h> +#include <linux/user_namespace.h> + +static struct kmem_cache *task_exec_state_cachep; + +static void __free_task_exec_state(struct rcu_head *rcu) +{ + struct task_exec_state *exec_state = container_of(rcu, struct task_exec_state, rcu); + + put_user_ns(exec_state->user_ns); + kmem_cache_free(task_exec_state_cachep, exec_state); +} + +void put_task_exec_state(struct task_exec_state *exec_state) +{ + if (exec_state && refcount_dec_and_test(&exec_state->count)) + call_rcu(&exec_state->rcu, __free_task_exec_state); +} + +struct task_exec_state *alloc_task_exec_state(struct user_namespace *user_ns) +{ + struct task_exec_state *exec_state; + + exec_state = kmem_cache_alloc(task_exec_state_cachep, GFP_KERNEL); + if (!exec_state) + return NULL; + refcount_set(&exec_state->count, 1); + exec_state->dumpable = TASK_DUMPABLE_OFF; + exec_state->user_ns = get_user_ns(user_ns); + return exec_state; +} + +struct task_exec_state *task_exec_state_rcu(const struct task_struct *tsk) +{ + struct task_exec_state *exec_state; + + exec_state = rcu_dereference_check(tsk->exec_state, + lockdep_is_held(&tsk->alloc_lock)); + WARN_ON_ONCE(!exec_state); + return exec_state; +} + +struct task_exec_state *task_exec_state_replace(struct task_struct *tsk, + struct task_exec_state *exec_state) +{ + /* + * Updates must hold both locks so callers needing a consistent + * snapshot of mm + dumpability are covered. + */ + lockdep_assert_held(&tsk->alloc_lock); + lockdep_assert_held_write(&tsk->signal->exec_update_lock); + + return rcu_replace_pointer(tsk->exec_state, exec_state, true); +} + +/* + * The non-CLONE_VM clone path: allocate a fresh exec_state and + * inherit the parent's dumpable mode and user_ns reference. CLONE_VM + * siblings refcount-share via copy_exec_state() in fork.c; only this + * path and execve() ever allocate. + */ +int task_exec_state_copy(struct task_struct *tsk) +{ + struct task_exec_state *src, *dst; + + src = rcu_dereference_protected(current->exec_state, true); + dst = alloc_task_exec_state(src->user_ns); + if (!dst) + return -ENOMEM; + dst->dumpable = READ_ONCE(src->dumpable); + rcu_assign_pointer(tsk->exec_state, dst); + return 0; +} + +/* + * Store TASK_DUMPABLE_* on current->exec_state. All callers + * (commit_creds, begin_new_exec, prctl(PR_SET_DUMPABLE)) act on the + * running task, which guarantees ->exec_state is allocated and cannot + * be replaced under us. + */ +void task_exec_state_set_dumpable(enum task_dumpable value) +{ + struct task_exec_state *exec_state; + + if (WARN_ON_ONCE(value > TASK_DUMPABLE_ROOT)) + value = TASK_DUMPABLE_OFF; + + exec_state = rcu_dereference_protected(current->exec_state, true); + /* mm-less tasks share init_task's exec_state; never mutate it */ + if (WARN_ON_ONCE(exec_state == &init_task_exec_state)) + return; + WRITE_ONCE(exec_state->dumpable, value); +} + +enum task_dumpable task_exec_state_get_dumpable(struct task_struct *task) +{ + struct task_exec_state *exec_state; + + guard(rcu)(); + exec_state = rcu_dereference(task->exec_state); + return READ_ONCE(exec_state->dumpable); +} + +void __init exec_state_init(void) +{ + task_exec_state_cachep = kmem_cache_create("task_exec_state", + sizeof(struct task_exec_state), 0, + SLAB_HWCACHE_ALIGN | SLAB_PANIC | SLAB_ACCOUNT, + NULL); +} |
