linux/arch/um/os-Linux
Jeff Dike 508a92741a uml: fix irqstack crash
This patch fixes a crash caused by an interrupt coming in when an IRQ stack
is being torn down.  When this happens, handle_signal will loop, setting up
the IRQ stack again because the tearing down had finished, and handling
whatever signals had come in.

However, to_irq_stack returns a mask of pending signals to be handled, plus
bit zero is set if the IRQ stack was already active, and thus shouldn't be
torn down.  This causes a problem because when handle_signal goes around
the loop, sig will be zero, and to_irq_stack will duly set bit zero in the
returned mask, faking handle_signal into believing that it shouldn't tear
down the IRQ stack and return thread_info pointers back to their original
values.

This will eventually cause a crash, as the IRQ stack thread_info will
continue pointing to the original task_struct and an interrupt will look
into it after it has been freed.

The fix is to stop passing a signal number into to_irq_stack.  Rather, the
pending signals mask is initialized beforehand with the bit for sig already
set.  References to sig in to_irq_stack can be replaced with references to
the mask.

[akpm@linux-foundation.org: use UL]
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-09-19 11:24:18 -07:00
..
drivers uml: Eliminate kernel allocator wrappers 2007-07-16 09:05:38 -07:00
include Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
skas uml: SIGIO support cleanup 2007-07-16 09:05:38 -07:00
sys-i386 uml: iRQ stacks 2007-05-11 08:29:34 -07:00
sys-x86_64 uml: fix x86_64 core dump crash 2007-08-31 01:42:22 -07:00
aio.c uml: fix aio compilation bug 2007-07-24 12:24:58 -07:00
elf_aux.c [PATCH] uml: host VDSO fix 2007-03-01 14:53:38 -08:00
execvp.c [PATCH] uml: make execvp safe for our usage 2006-11-25 13:28:34 -08:00
file.c uml: use correct type in BLKGETSIZE ioctl 2007-09-19 11:24:17 -07:00
helper.c uml: Eliminate kernel allocator wrappers 2007-07-16 09:05:38 -07:00
irq.c uml: remove user_util.h 2007-05-07 12:13:01 -07:00
main.c uml: Eliminate kernel allocator wrappers 2007-07-16 09:05:38 -07:00
Makefile [PATCH] uml: make execvp safe for our usage 2006-11-25 13:28:34 -08:00
mem.c uml: convert libc layer to call read and write 2007-05-07 12:13:03 -07:00
process.c uml: more __init annotations 2007-07-24 12:24:58 -07:00
sigio.c uml: Eliminate kernel allocator wrappers 2007-07-16 09:05:38 -07:00
signal.c uml: fix irqstack crash 2007-09-19 11:24:18 -07:00
start_up.c uml: remove PAGE_SIZE from libc code 2007-06-16 13:16:16 -07:00
time.c uml: remove user_util.h 2007-05-07 12:13:01 -07:00
tls.c [PATCH] uml: include tidying 2006-11-03 12:27:59 -08:00
trap.c uml: remove user_util.h 2007-05-07 12:13:01 -07:00
tt.c uml: remove page_size() 2007-05-07 12:13:02 -07:00
tty_log.c uml: convert libc layer to call read and write 2007-05-07 12:13:03 -07:00
tty.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
uaccess.c [PATCH] uml: Use klibc setjmp/longjmp 2006-09-26 08:49:05 -07:00
umid.c [PATCH] uml: umid tidying 2007-02-11 10:51:24 -08:00
user_syms.c uml: fix string exporting on UML/i386 2007-07-24 12:24:58 -07:00
util.c uml: remove task_protections 2007-05-11 08:29:33 -07:00