Commit 3d2a71a596 ("x86, traps: converge
do_debug handlers") changed the preemption disable logic of do_debug()
so vm86_handle_trap() is called with preemption disabled resulting in:
BUG: sleeping function called from invalid context at include/linux/kernel.h:155
in_atomic(): 1, irqs_disabled(): 0, pid: 3005, name: dosemu.bin
Pid: 3005, comm: dosemu.bin Tainted: G W 2.6.29-rc1 #51
Call Trace:
[<c050d669>] copy_to_user+0x33/0x108
[<c04181f4>] save_v86_state+0x65/0x149
[<c0418531>] handle_vm86_trap+0x20/0x8f
[<c064e345>] do_debug+0x15b/0x1a4
[<c064df1f>] debug_stack_correct+0x27/0x2c
[<c040365b>] sysenter_do_call+0x12/0x2f
BUG: scheduling while atomic: dosemu.bin/3005/0x10000001
Restore the original calling convention and reenable preemption before
calling handle_vm86_trap().
Reported-by: Michal Suchanek <hramrach@centrum.cz>
Cc: stable@kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
be716615fe