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From 521c003737f893ff4a6c6e95b0d1555d28a86252 Mon Sep 17 00:00:00 2001
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From: John Snow <jsnow@redhat.com>
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Date: Tue, 24 Jul 2018 12:50:06 +0200
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Subject: [PATCH 232/268] block: Fix parameter checking in
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 bdrv_co_copy_range_internal
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RH-Author: John Snow <jsnow@redhat.com>
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Message-id: <20180718225511.14878-15-jsnow@redhat.com>
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Patchwork-id: 81411
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O-Subject: [RHEL-7.6 qemu-kvm-rhev PATCH 14/35] block: Fix parameter checking in bdrv_co_copy_range_internal
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Bugzilla: 1207657
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RH-Acked-by: Eric Blake <eblake@redhat.com>
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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RH-Acked-by: Fam Zheng <famz@redhat.com>
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From: Fam Zheng <famz@redhat.com>
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src may be NULL if BDRV_REQ_ZERO_WRITE flag is set, in this case only
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check dst and dst->bs. This bug was introduced when moving in the
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request tracking code from bdrv_co_copy_range, in 37aec7d75eb.
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This especially fixes the possible segfault when initializing src_bs
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with a NULL src.
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Signed-off-by: Fam Zheng <famz@redhat.com>
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Message-id: 20180703023758.14422-2-famz@redhat.com
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Reviewed-by: Jeff Cody <jcody@redhat.com>
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Signed-off-by: Jeff Cody <jcody@redhat.com>
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(cherry picked from commit d4d3e5a0d53a57282955e8a3ed7acc1ca90552d9)
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Signed-off-by: John Snow <jsnow@redhat.com>
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---
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 block/io.c | 28 +++++++++++++++-------------
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 1 file changed, 15 insertions(+), 13 deletions(-)
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diff --git a/block/io.c b/block/io.c
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index 136a5d0..7981239 100644
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--- a/block/io.c
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+++ b/block/io.c
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@@ -2848,17 +2848,11 @@ static int coroutine_fn bdrv_co_copy_range_internal(BdrvChild *src,
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                                                     bool recurse_src)
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 {
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     BdrvTrackedRequest src_req, dst_req;
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-    BlockDriverState *src_bs = src->bs;
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-    BlockDriverState *dst_bs = dst->bs;
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     int ret;
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-    if (!src || !dst || !src->bs || !dst->bs) {
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+    if (!dst || !dst->bs) {
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         return -ENOMEDIUM;
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     }
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-    ret = bdrv_check_byte_request(src->bs, src_offset, bytes);
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-    if (ret) {
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-        return ret;
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-    }
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     ret = bdrv_check_byte_request(dst->bs, dst_offset, bytes);
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     if (ret) {
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@@ -2868,17 +2862,25 @@ static int coroutine_fn bdrv_co_copy_range_internal(BdrvChild *src,
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         return bdrv_co_pwrite_zeroes(dst, dst_offset, bytes, flags);
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     }
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+    if (!src || !src->bs) {
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+        return -ENOMEDIUM;
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+    }
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+    ret = bdrv_check_byte_request(src->bs, src_offset, bytes);
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+    if (ret) {
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+        return ret;
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+    }
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+    
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     if (!src->bs->drv->bdrv_co_copy_range_from
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         || !dst->bs->drv->bdrv_co_copy_range_to
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         || src->bs->encrypted || dst->bs->encrypted) {
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         return -ENOTSUP;
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     }
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-    bdrv_inc_in_flight(src_bs);
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-    bdrv_inc_in_flight(dst_bs);
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-    tracked_request_begin(&src_req, src_bs, src_offset,
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+    bdrv_inc_in_flight(src->bs);
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+    bdrv_inc_in_flight(dst->bs);
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+    tracked_request_begin(&src_req, src->bs, src_offset,
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                           bytes, BDRV_TRACKED_READ);
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-    tracked_request_begin(&dst_req, dst_bs, dst_offset,
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+    tracked_request_begin(&dst_req, dst->bs, dst_offset,
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                           bytes, BDRV_TRACKED_WRITE);
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     wait_serialising_requests(&src_req);
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@@ -2896,8 +2898,8 @@ static int coroutine_fn bdrv_co_copy_range_internal(BdrvChild *src,
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     }
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     tracked_request_end(&src_req);
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     tracked_request_end(&dst_req);
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-    bdrv_dec_in_flight(src_bs);
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-    bdrv_dec_in_flight(dst_bs);
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+    bdrv_dec_in_flight(src->bs);
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+    bdrv_dec_in_flight(dst->bs);
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     return ret;
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 }
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-- 
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1.8.3.1
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