在2023年11月30日十一月 下午4:36，Thomas Bogendoerfer写道：
io_uring sets up the io worker kernel thread via a syscall out of an user space prrocess. This process might have used FPU and since copy_thread() didn't clear FPU states for kernel threads a BUG() is triggered for using FPU inside kernel. Move code around to always clear FPU state for user and kernel threads.
Cc: stable@vger.kernel.org Reported-by: Aurelien Jarno aurel32@debian.org Closes: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1055021 Signed-off-by: Thomas Bogendoerfer tsbogend@alpha.franken.de
Reviewed-by: Jiaxun Yang jiaxun.yang@flygoat.com
Perhaps Suggested-by: Jiaxun Yang jiaxun.yang@flygoat.com
As well :-)
Thanks - Jiaxun
arch/mips/kernel/process.c | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-)
diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c index 5387ed0a5186..b630604c577f 100644 --- a/arch/mips/kernel/process.c +++ b/arch/mips/kernel/process.c @@ -121,6 +121,19 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) /* Put the stack after the struct pt_regs. */ childksp = (unsigned long) childregs; p->thread.cp0_status = (read_c0_status() & ~(ST0_CU2|ST0_CU1)) | ST0_KERNEL_CUMASK;
- /*
* New tasks lose permission to use the fpu. This accelerates context* switching for most programs since they don't use the fpu.*/- clear_tsk_thread_flag(p, TIF_USEDFPU);
- clear_tsk_thread_flag(p, TIF_USEDMSA);
- clear_tsk_thread_flag(p, TIF_MSA_CTX_LIVE);
+#ifdef CONFIG_MIPS_MT_FPAFF
- clear_tsk_thread_flag(p, TIF_FPUBOUND);
+#endif /* CONFIG_MIPS_MT_FPAFF */
- if (unlikely(args->fn)) { /* kernel thread */ unsigned long status = p->thread.cp0_status;
@@ -149,20 +162,8 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) p->thread.reg29 = (unsigned long) childregs; p->thread.reg31 = (unsigned long) ret_from_fork;
/*
* New tasks lose permission to use the fpu. This accelerates context* switching for most programs since they don't use the fpu.*/childregs->cp0_status &= ~(ST0_CU2|ST0_CU1);
clear_tsk_thread_flag(p, TIF_USEDFPU);
clear_tsk_thread_flag(p, TIF_USEDMSA);
clear_tsk_thread_flag(p, TIF_MSA_CTX_LIVE);
-#ifdef CONFIG_MIPS_MT_FPAFF
- clear_tsk_thread_flag(p, TIF_FPUBOUND);
-#endif /* CONFIG_MIPS_MT_FPAFF */
#ifdef CONFIG_MIPS_FP_SUPPORT atomic_set(&p->thread.bd_emu_frame, BD_EMUFRAME_NONE);
#endif
2.35.3