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author | Roland McGrath <roland@redhat.com> | 2008-02-28 19:57:07 -0800 |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-03-11 17:11:54 +0100 |
commit | 40f0933d51f4cba26a5c009a26bb230f4514c1b6 (patch) | |
tree | 29a55b7ae8ca7488a9d84fb9de234cff9f8f80b4 /include/asm-x86 | |
parent | 9a46d7e5b63903a70cd96c2c1391a7a26a8dbec9 (diff) |
x86: ia32 syscall restart fix
The code to restart syscalls after signals depends on checking for a
negative orig_ax, and for particular negative -ERESTART* values in ax.
These fields are 64 bits and for a 32-bit task they get zero-extended.
The syscall restart behavior is lost, a regression from a native 32-bit
kernel and from 64-bit tasks' behavior.
This patch fixes the problem by doing sign-extension where it matters.
For orig_ax, the only time the value should be -1 but winds up as
0x0ffffffff is via a 32-bit ptrace call. So the patch changes ptrace to
sign-extend the 32-bit orig_eax value when it's stored; it doesn't
change the checks on orig_ax, though it uses the new current_syscall()
inline to better document the subtle importance of the used of
signedness there.
The ax value is stored a lot of ways and it seems hard to get them all
sign-extended at their origins. So for that, we use the
current_syscall_ret() to sign-extend it only for 32-bit tasks at the
time of the -ERESTART* comparisons.
Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/asm-x86')
0 files changed, 0 insertions, 0 deletions