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linux-next/arch/powerpc
Jim Keniston 8bf1101bd5 [PATCH] kprobes: Fix return probes on sys_execve
Fix a bug in kprobes that can cause an Oops or even a crash when a return
probe is installed on one of the following functions: sys_execve,
do_execve, load_*_binary, flush_old_exec, or flush_thread.  The fix is to
remove the call to kprobe_flush_task() in flush_thread().  This fix has
been tested on all architectures for which the return-probes feature has
been implemented (i386, x86_64, ppc64, ia64).  Please apply.

BACKGROUND

Up to now, we have called kprobe_flush_task() under two situations: when a
task exits, and when it execs.  Flushing kretprobe_instances on exit is
correct because (a) do_exit() doesn't return, and (b) one or more
return-probed functions may be active when a task calls do_exit().  Neither
is the case for sys_execve() and its callees.

Initially, the mistaken call to kprobe_flush_task() on exec was harmless
because we put the "real" return address of each active probed function
back in the stack, just to be safe, when we recycled its
kretprobe_instance.  When support for ppc64 and ia64 was added, this safety
measure couldn't be employed, and was eventually dropped even for i386 and
x86_64.  sys_execve() and its callees were informally blacklisted for
return probes until this fix was developed.

Acked-by: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Signed-off-by: Jim Keniston <jkenisto@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-23 16:08:39 -08:00
..
boot [PATCH] ppc boot: replace string labels with numbers 2005-11-18 13:18:16 +11:00
configs powerpc: Move defconfig over and remove remaining arch/ppc64 files 2005-11-18 16:39:08 +11:00
kernel [PATCH] kprobes: Fix return probes on sys_execve 2005-11-23 16:08:39 -08:00
lib powerpc: Fix find_next_bit on 32-bit 2005-11-10 12:01:41 +11:00
mm [PATCH] mm: powerpc init_mm without ptlock 2005-11-23 16:08:38 -08:00
oprofile [PATCH] Update email address for Kumar 2005-11-13 18:14:10 -08:00
platforms powerpc: Fix bug in timebase synchronization on 32-bit SMP powermac 2005-11-19 21:24:55 +11:00
sysdev [PATCH] powerpc: Fix setting MPIC priority 2005-11-19 14:19:13 +11:00
xmon [PATCH] powerpc-xmon-build-fix 2005-11-13 18:14:13 -08:00
Kconfig [PATCH] Remove SPAN_OTHER_NODES config definition 2005-11-18 14:45:54 +11:00
Kconfig.debug [PATCH] Move Kprobes and Oprofile to "Instrumentation Support" menu 2005-11-07 07:53:35 -08:00
Makefile powerpc: Move defconfig over and remove remaining arch/ppc64 files 2005-11-18 16:39:08 +11:00