The patch titled
fix broken vm86 interrupt/signal handling
has been removed from the -mm tree. Its filename is
fix-broken-vm86-interrupt-signal-handling.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: fix broken vm86 interrupt/signal handling
From: "Aleksey Gorelov" <Aleksey_Gorelov@xxxxxxxxxxx>
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.
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@xxxxxxxxxxx>
Cc: Atsushi Nemoto <anemo@xxxxxxxxxxxxx>
Cc: Roland McGrath <roland@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
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
--- a/arch/i386/kernel/entry.S~fix-broken-vm86-interrupt-signal-handling
+++ a/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 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
_
Patches currently in -mm which might be from Aleksey_Gorelov@xxxxxxxxxxx are
origin.patch
-
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