diff options
author | Roland McGrath <roland@redhat.com> | 2009-09-22 20:12:07 -0700 |
---|---|---|
committer | Roland McGrath <roland@redhat.com> | 2009-09-22 22:49:24 -0700 |
commit | 8cb3ed13935b9b523c2de7afc8f68473fe1d4531 (patch) | |
tree | 8c9d53ac4e9facc5750cc6bd7bd07260845b9797 /arch/powerpc/include/asm/user.h | |
parent | 08ff18e299b1a1c91f4911fe9f35c4550218c73f (diff) |
x86: ptrace: set TS_COMPAT when 32-bit ptrace sets orig_eax>=0
The 32-bit ptrace syscall on a 64-bit kernel (32-bit debugger on
32-bit task) behaves differently than a native 32-bit kernel. When
setting a register state of orig_eax>=0 and eax=-ERESTART* when the
debugged task is NOT on its way out of a 32-bit syscall, the task will
fail to do the syscall restart logic that it should do.
Test case available at http://sources.redhat.com/cgi-bin/cvsweb.cgi/~checkout~/tests/ptrace-tests/tests/erestartsys-trap.c?cvsroot=systemtap
This happens because the 32-bit ptrace syscall sets eax=0xffffffff
when it sets orig_eax>=0. The resuming task will not sign-extend this
for the -ERESTART* check because TS_COMPAT is not set. (So the task
thinks it is restarting after a 64-bit syscall, not a 32-bit one.)
The fix is to have 32-bit ptrace calls set TS_COMPAT when setting
orig_eax>=0. This ensures that the 32-bit syscall restart logic
will apply when the child resumes.
Signed-off-by: Roland McGrath <roland@redhat.com>
Diffstat (limited to 'arch/powerpc/include/asm/user.h')
0 files changed, 0 insertions, 0 deletions