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https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
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b3b9cb11aa
On do_exit() when a task is exiting, if a unwind is requested and the deferred user stacktrace is deferred via the task_work, the task_work callback is called after exit_mm() is called in do_exit(). This means that the user stack trace will not be retrieved and an empty stack is created. Instead, add a function unwind_deferred_task_exit() and call it just before exit_mm() so that the unwinder can call the requested callbacks with the user space stack. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Josh Poimboeuf <jpoimboe@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Indu Bhagat <indu.bhagat@oracle.com> Cc: "Jose E. Marchesi" <jemarch@gnu.org> Cc: Beau Belgrave <beaub@linux.microsoft.com> Cc: Jens Remus <jremus@linux.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Florian Weimer <fweimer@redhat.com> Cc: Sam James <sam@gentoo.org> Link: https://lore.kernel.org/20250729182406.504259474@kernel.org Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
82 lines
2.3 KiB
C
82 lines
2.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_UNWIND_USER_DEFERRED_H
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#define _LINUX_UNWIND_USER_DEFERRED_H
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#include <linux/task_work.h>
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#include <linux/unwind_user.h>
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#include <linux/unwind_deferred_types.h>
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struct unwind_work;
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typedef void (*unwind_callback_t)(struct unwind_work *work, struct unwind_stacktrace *trace, u64 cookie);
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struct unwind_work {
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struct list_head list;
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unwind_callback_t func;
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int bit;
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};
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#ifdef CONFIG_UNWIND_USER
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enum {
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UNWIND_PENDING_BIT = 0,
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UNWIND_USED_BIT,
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};
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enum {
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UNWIND_PENDING = BIT(UNWIND_PENDING_BIT),
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/* Set if the unwinding was used (directly or deferred) */
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UNWIND_USED = BIT(UNWIND_USED_BIT)
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};
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void unwind_task_init(struct task_struct *task);
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void unwind_task_free(struct task_struct *task);
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int unwind_user_faultable(struct unwind_stacktrace *trace);
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int unwind_deferred_init(struct unwind_work *work, unwind_callback_t func);
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int unwind_deferred_request(struct unwind_work *work, u64 *cookie);
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void unwind_deferred_cancel(struct unwind_work *work);
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void unwind_deferred_task_exit(struct task_struct *task);
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static __always_inline void unwind_reset_info(void)
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{
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struct unwind_task_info *info = ¤t->unwind_info;
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unsigned long bits;
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/* Was there any unwinding? */
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if (unlikely(info->unwind_mask)) {
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bits = info->unwind_mask;
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do {
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/* Is a task_work going to run again before going back */
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if (bits & UNWIND_PENDING)
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return;
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} while (!try_cmpxchg(&info->unwind_mask, &bits, 0UL));
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current->unwind_info.id.id = 0;
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if (unlikely(info->cache)) {
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info->cache->nr_entries = 0;
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info->cache->unwind_completed = 0;
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}
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}
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}
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#else /* !CONFIG_UNWIND_USER */
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static inline void unwind_task_init(struct task_struct *task) {}
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static inline void unwind_task_free(struct task_struct *task) {}
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static inline int unwind_user_faultable(struct unwind_stacktrace *trace) { return -ENOSYS; }
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static inline int unwind_deferred_init(struct unwind_work *work, unwind_callback_t func) { return -ENOSYS; }
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static inline int unwind_deferred_request(struct unwind_work *work, u64 *timestamp) { return -ENOSYS; }
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static inline void unwind_deferred_cancel(struct unwind_work *work) {}
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static inline void unwind_deferred_task_exit(struct task_struct *task) {}
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static inline void unwind_reset_info(void) {}
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#endif /* !CONFIG_UNWIND_USER */
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#endif /* _LINUX_UNWIND_USER_DEFERRED_H */
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