Skip to main content

Browse the archive

https://github.com/torvalds/linux
05 April 2024, 19:05:47 UTC
Revision d198d499148a0c64a41b3aba9e7dd43772832b91 authored by Igor Mammedov on 01 September 2011, 11:46:55 UTC, committed by Konrad Rzeszutek Wilk on 01 September 2011, 16:54:42 UTC 
xen: x86_32: do not enable iterrupts when returning from exception in interrupt context
 
If vmalloc page_fault happens inside of interrupt handler with interrupts
disabled then on exit path from exception handler when there is no pending
interrupts, the following code (arch/x86/xen/xen-asm_32.S:112):

	cmpw $0x0001, XEN_vcpu_info_pending(%eax)
	sete XEN_vcpu_info_mask(%eax)

will enable interrupts even if they has been previously disabled according to
eflags from the bounce frame (arch/x86/xen/xen-asm_32.S:99)

	testb $X86_EFLAGS_IF>>8, 8+1+ESP_OFFSET(%esp)
	setz XEN_vcpu_info_mask(%eax)

Solution is in setting XEN_vcpu_info_mask only when it should be set
according to
	cmpw $0x0001, XEN_vcpu_info_pending(%eax)
but not clearing it if there isn't any pending events.

Reproducer for bug is attached to RHBZ 707552

CC: stable@kernel.org
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Acked-by: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
1 parent d312ae8
History
Tip revision: d198d499148a0c64a41b3aba9e7dd43772832b91 authored by Igor Mammedov on 01 September 2011, 11:46:55 UTC
xen: x86_32: do not enable iterrupts when returning from exception in interrupt context
Tip revision: d198d49
File Mode Size
Documentation
arch
block
crypto
drivers
firmware
fs
include
init
ipc
kernel
lib
mm
net
samples
scripts
security
sound
tools
usr
virt
.gitignore -rw-r--r-- 1014 bytes
.mailmap -rw-r--r-- 4.1 KB
COPYING -rw-r--r-- 18.3 KB
CREDITS -rw-r--r-- 92.3 KB
Kbuild -rw-r--r-- 2.4 KB
Kconfig -rw-r--r-- 252 bytes
MAINTAINERS -rw-r--r-- 195.4 KB
Makefile -rw-r--r-- 52.3 KB
README -rw-r--r-- 17.0 KB
REPORTING-BUGS -rw-r--r-- 3.3 KB

README

back to top