325d6f5593
Iff the parent has TIF_DEBUG set, _and_ clone_flags includes CLONE_PTRACE we should set the TIF_DEBUG flag for the child and increment the ocd refcount. Otherwise, the TIF_DEBUG flag must be unset. Currently, the child inherits TIF_DEBUG from the parent before copy_thread is called, so TIF_DEBUG may be already be set before we determine whether the child is supposed to inherit debugging capabilities from the parent or not. This means that ocd_enable() won't increment the refcount, because TIF_DEBUG is already set, and that TIF_DEBUG will be set for processes that aren't being debugged. This leads to a refcounting asymmetry, which may show up as ------------[ cut here ]------------ Badness at arch/avr32/kernel/ocd.c:73 PC is at ocd_disable+0x34/0x60 LR is at put_lock_stats+0xa/0x20 as reported by David Brownell. Happens when strace'ing a process that forks a new child process, e.g. "strace mount -tjffs2 mtd1 /mnt", and subsequently killing the child process (e.g. "umount /mnt".) Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com> |
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.. | ||
asm-offsets.c | ||
avr32_ksyms.c | ||
cpu.c | ||
entry-avr32b.S | ||
head.S | ||
init_task.c | ||
irq.c | ||
kprobes.c | ||
Makefile | ||
module.c | ||
nmi_debug.c | ||
ocd.c | ||
process.c | ||
ptrace.c | ||
semaphore.c | ||
setup.c | ||
signal.c | ||
stacktrace.c | ||
switch_to.S | ||
sys_avr32.c | ||
syscall-stubs.S | ||
syscall_table.S | ||
time.c | ||
traps.c | ||
vmlinux.lds.S |