linux/arch/um/kernel
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
..
skas uml: more __init annotations 2007-07-24 12:24:58 -07:00
tt uml: remove task_protections 2007-05-11 08:29:33 -07:00
asm-offsets.c [PATCH] uml: fix missing KBUILD_BASENAME 2006-01-11 18:42:09 -08:00
config.c.in Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
dyn.lds.S uml: fix linker script alignment bugs 2007-08-31 01:42:22 -07:00
exec.c Remove fs.h from mm.h 2007-07-29 17:09:29 -07:00
exitcode.c uml: get declaration of simple_strtoul 2007-06-08 17:23:33 -07:00
gmon_syms.c [PATCH] uml: fix gcov support 2006-09-27 08:26:16 -07:00
gprof_syms.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
init_task.c Remove fs.h from mm.h 2007-07-29 17:09:29 -07:00
initrd.c uml: rename os_{read_write}_file_k back to os_{read_write}_file 2007-05-07 12:13:03 -07:00
irq.c uml: fix irqstack crash 2007-09-19 11:24:18 -07:00
ksyms.c uml: rename os_{read_write}_file_k back to os_{read_write}_file 2007-05-07 12:13:03 -07:00
Makefile [PATCH] uml: delete unused file 2007-02-11 10:51:22 -08:00
mem.c uml: more __init annotations 2007-07-24 12:24:58 -07:00
physmem.c uml: more __init annotations 2007-07-24 12:24:58 -07:00
process.c uml: Eliminate kernel allocator wrappers 2007-07-16 09:05:38 -07:00
ptrace.c PTRACE_POKEDATA consolidation 2007-07-17 10:23:03 -07:00
reboot.c uml: remove user_util.h 2007-05-07 12:13:01 -07:00
sigio.c uml: rename os_{read_write}_file_k back to os_{read_write}_file 2007-05-07 12:13:03 -07:00
signal.c uml: remove user_util.h 2007-05-07 12:13:01 -07:00
smp.c uml: rename os_{read_write}_file_k back to os_{read_write}_file 2007-05-07 12:13:03 -07:00
syscall.c Remove fs.h from mm.h 2007-07-29 17:09:29 -07:00
sysrq.c uml: remove user_util.h 2007-05-07 12:13:01 -07:00
time.c uml: an idle system should have zero load average 2007-05-08 11:14:57 -07:00
tlb.c uml: more page fault path trimming 2007-05-07 12:13:04 -07:00
trap.c mm: fault feedback #2 2007-07-19 10:04:41 -07:00
uaccess.c [PATCH] uml: separate libc-dependent uaccess code 2005-11-07 07:53:31 -08:00
um_arch.c uml: remove task_protections 2007-05-11 08:29:33 -07:00
umid.c [PATCH] uml: umid tidying 2007-02-11 10:51:24 -08:00
uml.lds.S uml: fix linker script alignment bugs 2007-08-31 01:42:22 -07:00
vmlinux.lds.S [PATCH] uml: tidy biarch gcc support 2006-07-14 21:53:52 -07:00