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| author | Aleksey Gorelov <Aleksey_Gorelov@Phoenix.com> | 2006-06-27 11:53:48 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-06-28 02:32:38 +0200 |
| commit | 4031ff388138b58e5cd472dccce38828bcb8c706 (patch) | |
| tree | f2c88fdcdef3ec9880d23ce271f14e95f7aa1cf5 | |
| parent | [PATCH] i386: use C code for current_thread_info() (diff) | |
| download | linux-4031ff388138b58e5cd472dccce38828bcb8c706.tar.xz linux-4031ff388138b58e5cd472dccce38828bcb8c706.zip | |
[PATCH] fix broken vm86 interrupt/signal handling
Commit c3ff8ec31c1249d268cd11390649768a12bec1b9 ("[PATCH] i386: Don't
miss pending signals returning to user mode after signal processing")
meant that vm86 interrupt/signal handling got broken for the 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.
No in-tree usage of vm86() from kernel space exists, but I've heard
about a number of projects out there which use vm86 calls from kernel,
one of them being this, for instance:
http://dev.gentoo.org/~spock/projects/vesafb-tng/
The following patch fixes the issue.
Signed-off-by: Aleksey Gorelov <aleksey_gorelov@phoenix.com>
Cc: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
| -rw-r--r-- | arch/i386/kernel/entry.S | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/arch/i386/kernel/entry.S b/arch/i386/kernel/entry.S index 8713e0248a0b..e8d2630fd19a 100644 --- a/arch/i386/kernel/entry.S +++ b/arch/i386/kernel/entry.S @@ -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 signals and # 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 |