6.15-stable review patch. If anyone has any objections, please let me know.
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From: Thomas Weißschuh thomas.weissschuh@linutronix.de
[ Upstream commit b9e2f2246eb2b5617d53af7b5e4e1b8c916f26a8 ]
The thread flags may change during their processing. For example a task_work can queue a new signal to be sent. This signal should be delivered before returning to usespace again.
Evaluate the flags repeatedly similar to other architectures.
Signed-off-by: Thomas Weißschuh thomas.weissschuh@linutronix.de Reviewed-by: Nam Cao namcao@linutronix.de Link: https://patch.msgid.link/20250704-uml-thread_flags-v1-1-0e293fd8d627@linutro... Signed-off-by: Johannes Berg johannes.berg@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/um/include/asm/thread_info.h | 4 ++++ arch/um/kernel/process.c | 20 ++++++++++++-------- 2 files changed, 16 insertions(+), 8 deletions(-)
diff --git a/arch/um/include/asm/thread_info.h b/arch/um/include/asm/thread_info.h index f9ad06fcc991..eb9b3a6d99e8 100644 --- a/arch/um/include/asm/thread_info.h +++ b/arch/um/include/asm/thread_info.h @@ -50,7 +50,11 @@ struct thread_info { #define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL) #define _TIF_MEMDIE (1 << TIF_MEMDIE) #define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT) +#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME) #define _TIF_SECCOMP (1 << TIF_SECCOMP) #define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP)
+#define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL | \ + _TIF_NOTIFY_RESUME) + #endif diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c index 0cd6fad3d908..1be644de9e41 100644 --- a/arch/um/kernel/process.c +++ b/arch/um/kernel/process.c @@ -82,14 +82,18 @@ struct task_struct *__switch_to(struct task_struct *from, struct task_struct *to void interrupt_end(void) { struct pt_regs *regs = ¤t->thread.regs; - - if (need_resched()) - schedule(); - if (test_thread_flag(TIF_SIGPENDING) || - test_thread_flag(TIF_NOTIFY_SIGNAL)) - do_signal(regs); - if (test_thread_flag(TIF_NOTIFY_RESUME)) - resume_user_mode_work(regs); + unsigned long thread_flags; + + thread_flags = read_thread_flags(); + while (thread_flags & _TIF_WORK_MASK) { + if (thread_flags & _TIF_NEED_RESCHED) + schedule(); + if (thread_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) + do_signal(regs); + if (thread_flags & _TIF_NOTIFY_RESUME) + resume_user_mode_work(regs); + thread_flags = read_thread_flags(); + } }
int get_current_pid(void)