MIPS: Don't stomp on caller's ->regs[2] in copy_thread()
authorAl Viro <viro@ZenIV.linux.org.uk>
Thu, 4 Nov 2010 11:13:59 +0000 (11:13 +0000)
committerRalf Baechle <ralf@linux-mips.org>
Thu, 16 Dec 2010 18:10:52 +0000 (18:10 +0000)
commita989ff898f9740651d00388c33bdf4f2a7914920
tree9f8ca387b8773c19ca4f2556c509ef3381b86abd
parent2b3e50234eafc40a04f5f4a2b7bb24b506fd7e87
MIPS: Don't stomp on caller's ->regs[2] in copy_thread()

We never needed that (->regs[2] is overwritten on return from syscall paths
with return value of syscall, so storing it there early made no sense) and
with new restart logics since d27240bf7e61d2656de18e158ec910a902030847 it
has become really bad - we lose the original syscall number before the
place where we decide that we might need a syscall restart.

Note that for child we do need the assignment to regs[2] - it won't go
through the normal return from syscall path.

[Ralf: Issue found and reported by Lluís; initial investigations by me;
bug finally found and patch by Al; testing by me and Lluís.]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Lluís Batlle i Rossell <viriketo@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
arch/mips/kernel/process.c