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| author | Thomas Bogendoerfer <tsbogend@alpha.franken.de> | 2023-11-30 17:36:01 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-12-13 18:45:34 +0100 |
| commit | 6d9cbae4c032451d41c262cbf8b90018af0dbda0 (patch) | |
| tree | b23f21a0ebb778bc67a0f6865684feb0b0c86dfb | |
| parent | 43801359c8971cc49b4a4db5015fba77fbd09c32 (diff) | |
| download | linux-starfive-6d9cbae4c032451d41c262cbf8b90018af0dbda0.tar.gz linux-starfive-6d9cbae4c032451d41c262cbf8b90018af0dbda0.tar.bz2 linux-starfive-6d9cbae4c032451d41c262cbf8b90018af0dbda0.zip | |
MIPS: kernel: Clear FPU states when setting up kernel threads
commit a58a173444a68412bb08849bd81c679395f20ca0 upstream.
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
Suggested-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/mips/kernel/process.c | 25 |
1 files 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 |