From: "Aleksey Gorelov" This patch: http://www.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=c3ff8ec31c1249d268cd11390649768a12bec1b9 has broken vm86 interrupt/signal handling in case when vm86 is called from kernel space. In this scenario, if signal is pending because of vm86 interrupt, do_notify_resume/do_signal exits immediately due to user_mode() check, without processing any signals. Thus, resume_userspace handler is spinning in a tight loop with signal pending and TIF_SIGPENDING is set. Previously everything worked Ok. The following patch fixes the issue Signed-off-by: Aleksey Gorelov Cc: Atsushi Nemoto Cc: Roland McGrath Signed-off-by: Andrew Morton --- arch/i386/kernel/entry.S | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff -puN arch/i386/kernel/entry.S~fix-broken-vm86-interrupt-signal-handling arch/i386/kernel/entry.S --- devel/arch/i386/kernel/entry.S~fix-broken-vm86-interrupt-signal-handling 2006-06-09 15:22:02.000000000 -0700 +++ devel-akpm/arch/i386/kernel/entry.S 2006-06-09 15:22:02.000000000 -0700 @@ -83,6 +83,12 @@ VM_MASK = 0x00020000 #define resume_kernel restore_nocheck #endif +#ifdef CONFIG_VM86 +#define resume_userspace_sig check_userspace +#else +#define resume_userspace_sig resume_userspace +#endif + #define SAVE_ALL \ cld; \ pushl %es; \ @@ -211,6 +217,7 @@ ret_from_exception: preempt_stop ret_from_intr: GET_THREAD_INFO(%ebp) +check_userspace: movl EFLAGS(%esp), %eax # mix EFLAGS and CS movb CS(%esp), %al testl $(VM_MASK | 3), %eax @@ -415,7 +422,7 @@ work_notifysig: # deal with pending s # vm86-space xorl %edx, %edx call do_notify_resume - jmp resume_userspace + jmp resume_userspace_sig ALIGN work_notifysig_v86: @@ -428,7 +435,7 @@ work_notifysig_v86: movl %eax, %esp xorl %edx, %edx call do_notify_resume - jmp resume_userspace + jmp resume_userspace_sig #endif # perform syscall exit tracing _