Author: avg
Date: Wed May 27 15:23:12 2009
New Revision: 192899
URL: http://svn.freebsd.org/changeset/base/192899
Log:
linux_ioctl_cdrom: reduce stack usage
... by moving two ~2KB structures from stack to heap allocation.
I experienced stack overflow in linux emulation on i386 (8K stack)
when LINUX_DVD_READ_STRUCT ioctl was performed on atapicam cd
device and there was an error that resulted in additional quite
heavy stack use in cam layer.
Reviewed by: dchagin
Approved by: jhb (mentor)
Modified:
head/sys/compat/linux/linux_ioctl.c
Modified: head/sys/compat/linux/linux_ioctl.c
==============================================================================
--- head/sys/compat/linux/linux_ioctl.c Wed May 27 15:16:56 2009
(r192898)
+++ head/sys/compat/linux/linux_ioctl.c Wed May 27 15:23:12 2009
(r192899)
@@ -1556,23 +1556,28 @@ linux_ioctl_cdrom(struct thread *td, str
/* LINUX_CDROMAUDIOBUFSIZ */
case LINUX_DVD_READ_STRUCT: {
- l_dvd_struct lds;
- struct dvd_struct bds;
+ l_dvd_struct *lds;
+ struct dvd_struct *bds;
- error = copyin((void *)args->arg, &lds, sizeof(lds));
+ lds = malloc(sizeof(*lds), M_LINUX, M_WAITOK);
+ bds = malloc(sizeof(*bds), M_LINUX, M_WAITOK);
+ error = copyin((void *)args->arg, lds, sizeof(*lds));
if (error)
- break;
- error = linux_to_bsd_dvd_struct(&lds, &bds);
+ goto out;
+ error = linux_to_bsd_dvd_struct(lds, bds);
if (error)
- break;
- error = fo_ioctl(fp, DVDIOCREADSTRUCTURE, (caddr_t)&bds,
+ goto out;
+ error = fo_ioctl(fp, DVDIOCREADSTRUCTURE, (caddr_t)bds,
td->td_ucred, td);
if (error)
- break;
- error = bsd_to_linux_dvd_struct(&bds, &lds);
+ goto out;
+ error = bsd_to_linux_dvd_struct(bds, lds);
if (error)
- break;
- error = copyout(&lds, (void *)args->arg, sizeof(lds));
+ goto out;
+ error = copyout(lds, (void *)args->arg, sizeof(*lds));
+ out:
+ free(bds, M_LINUX);
+ free(lds, M_LINUX);
break;
}
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