Author: kib Date: Sat Mar 29 11:56:33 2014 New Revision: 263912 URL: http://svnweb.freebsd.org/changeset/base/263912
Log: Clear the kernel grab of the FPU state on fork. The pcb_save pointer is already correctly reset to the FPU user save area, only PCB_KERNFPU flag might leak from old thread state into the new state. For creation of the user-mode thread, the change is nop since corresponding syscall code does not use FPU. On the other hand, creation of a kernel thread forks from a thread selected arbitrary from proc0, which might use FPU. Reported and tested by: Chris Torek <[email protected]> Sponsored by: The FreeBSD Foundation MFC after: 1 week Modified: head/sys/amd64/amd64/vm_machdep.c head/sys/i386/i386/vm_machdep.c Modified: head/sys/amd64/amd64/vm_machdep.c ============================================================================== --- head/sys/amd64/amd64/vm_machdep.c Sat Mar 29 11:33:52 2014 (r263911) +++ head/sys/amd64/amd64/vm_machdep.c Sat Mar 29 11:56:33 2014 (r263912) @@ -446,7 +446,8 @@ cpu_set_upcall(struct thread *td, struct * values here. */ bcopy(td0->td_pcb, pcb2, sizeof(*pcb2)); - clear_pcb_flags(pcb2, PCB_FPUINITDONE | PCB_USERFPUINITDONE); + clear_pcb_flags(pcb2, PCB_FPUINITDONE | PCB_USERFPUINITDONE | + PCB_KERNFPU); pcb2->pcb_save = get_pcb_user_save_pcb(pcb2); bcopy(get_pcb_user_save_td(td0), pcb2->pcb_save, cpu_max_ext_state_size); Modified: head/sys/i386/i386/vm_machdep.c ============================================================================== --- head/sys/i386/i386/vm_machdep.c Sat Mar 29 11:33:52 2014 (r263911) +++ head/sys/i386/i386/vm_machdep.c Sat Mar 29 11:56:33 2014 (r263912) @@ -457,7 +457,8 @@ cpu_set_upcall(struct thread *td, struct * values here. */ bcopy(td0->td_pcb, pcb2, sizeof(*pcb2)); - pcb2->pcb_flags &= ~(PCB_NPXINITDONE | PCB_NPXUSERINITDONE); + pcb2->pcb_flags &= ~(PCB_NPXINITDONE | PCB_NPXUSERINITDONE | + PCB_KERNNPX); pcb2->pcb_save = &pcb2->pcb_user_save; /* _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "[email protected]"
