From: Oleg Drokin Date: Sat, 27 May 2017 03:40:33 +0000 (-0400) Subject: staging/lustre/lov: remove set_fs() call from lov_getstripe() X-Git-Tag: release-20171130_firefly~4^2~100^2~1^2~4^2~48 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=a365c707d2eecb0aa6f4cbdbedf072ce6b0a336c;p=firefly-linux-kernel-4.4.55.git staging/lustre/lov: remove set_fs() call from lov_getstripe() commit 0a33252e060e97ed3fbdcec9517672f1e91aaef3 upstream. lov_getstripe() calls set_fs(KERNEL_DS) so that it can handle a struct lov_user_md pointer from user- or kernel-space. This changes the behavior of copy_from_user() on SPARC and may result in a misaligned access exception which in turn oopses the kernel. In fact the relevant argument to lov_getstripe() is never called with a kernel-space pointer and so changing the address limits is unnecessary and so we remove the calls to save, set, and restore the address limits. Signed-off-by: John L. Hammond Reviewed-on: http://review.whamcloud.com/6150 Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-3221 Reviewed-by: Andreas Dilger Reviewed-by: Li Wei Signed-off-by: Oleg Drokin Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/staging/lustre/lustre/lov/lov_pack.c b/drivers/staging/lustre/lustre/lov/lov_pack.c index 2fb1e974cc70..e11b1001d1f6 100644 --- a/drivers/staging/lustre/lustre/lov/lov_pack.c +++ b/drivers/staging/lustre/lustre/lov/lov_pack.c @@ -399,18 +399,10 @@ int lov_getstripe(struct obd_export *exp, struct lov_stripe_md *lsm, struct lov_mds_md *lmmk = NULL; int rc, lmm_size; int lum_size; - mm_segment_t seg; if (!lsm) return -ENODATA; - /* - * "Switch to kernel segment" to allow copying from kernel space by - * copy_{to,from}_user(). - */ - seg = get_fs(); - set_fs(KERNEL_DS); - /* we only need the header part from user space to get lmm_magic and * lmm_stripe_count, (the header part is common to v1 and v3) */ lum_size = sizeof(struct lov_user_md_v1); @@ -485,6 +477,5 @@ int lov_getstripe(struct obd_export *exp, struct lov_stripe_md *lsm, obd_free_diskmd(exp, &lmmk); out_set: - set_fs(seg); return rc; }