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[Qemu-devel] [PULL v2 for-2.9 13/17] Revert "hostmem: fix QEMU crash by
From: |
Markus Armbruster |
Subject: |
[Qemu-devel] [PULL v2 for-2.9 13/17] Revert "hostmem: fix QEMU crash by 'info memdev'" |
Date: |
Wed, 22 Mar 2017 18:48:24 +0100 |
This reverts commit 1454d33f0507cb54d62ed80f494884157c9e7130.
The string input visitor regression fixed in the previous commit made
visit_type_uint16List() fail on empty input. query_memdev() calls it
via object_property_get_uint16List(). Because it doesn't expect it to
fail, it passes &error_abort, and duly crashes.
Commit 1454d33 "fixes" this crash by making
host_memory_backend_get_host_nodes() return a list containing just
MAX_NODES instead of the empty list. Papers over the regression, and
leads to bogus "info memdev" output, as shown below; revert.
I suspect that if we had bisected the crash back then, we would have
found and fixed the actual bug instead of papering over it.
To reproduce, run HMP command "info memdev" with
$ qemu-system-x86_64 --nodefaults -S -display none -monitor stdio -object
memory-backend-ram,id=mem1,size=4k
With this commit, "info memdev" prints
memory backend: mem1
size: 4096
merge: true
dump: true
prealloc: false
policy: default
host nodes:
exactly like before commit 74f24cb.
Between commit 1454d33 and this commit, it prints
memory backend: mem1
size: 4096
merge: true
dump: true
prealloc: false
policy: default
host nodes: 128
The last line is bogus.
Between commit 74f24cb and 1454d33, it crashes like this:
Unexpected error in parse_str() at
/work/armbru/tmp/qemu/qapi/string-input-visitor.c:126:
Parameter 'null' expects an int64 value or range
Aborted (core dumped)
Cc: Xiao Guangrong <address@hidden>
Cc: Paolo Bonzini <address@hidden>
Signed-off-by: Markus Armbruster <address@hidden>
Message-Id: <address@hidden>
Reviewed-by: Michael Roth <address@hidden>
Reviewed-by: Eric Blake <address@hidden>
---
backends/hostmem.c | 22 ++++++++--------------
1 file changed, 8 insertions(+), 14 deletions(-)
diff --git a/backends/hostmem.c b/backends/hostmem.c
index 162c218..89feb9e 100644
--- a/backends/hostmem.c
+++ b/backends/hostmem.c
@@ -64,14 +64,6 @@ out:
error_propagate(errp, local_err);
}
-static uint16List **host_memory_append_node(uint16List **node,
- unsigned long value)
-{
- *node = g_malloc0(sizeof(**node));
- (*node)->value = value;
- return &(*node)->next;
-}
-
static void
host_memory_backend_get_host_nodes(Object *obj, Visitor *v, const char *name,
void *opaque, Error **errp)
@@ -82,23 +74,25 @@ host_memory_backend_get_host_nodes(Object *obj, Visitor *v,
const char *name,
unsigned long value;
value = find_first_bit(backend->host_nodes, MAX_NODES);
-
- node = host_memory_append_node(node, value);
-
if (value == MAX_NODES) {
- goto out;
+ return;
}
+ *node = g_malloc0(sizeof(**node));
+ (*node)->value = value;
+ node = &(*node)->next;
+
do {
value = find_next_bit(backend->host_nodes, MAX_NODES, value + 1);
if (value == MAX_NODES) {
break;
}
- node = host_memory_append_node(node, value);
+ *node = g_malloc0(sizeof(**node));
+ (*node)->value = value;
+ node = &(*node)->next;
} while (true);
-out:
visit_type_uint16List(v, name, &host_nodes, errp);
}
--
2.7.4
- [Qemu-devel] [PULL v2 for-2.9 09/17] tests/qapi-schema: Make test-qapi.py print docs again, (continued)
- [Qemu-devel] [PULL v2 for-2.9 09/17] tests/qapi-schema: Make test-qapi.py print docs again, Markus Armbruster, 2017/03/22
- [Qemu-devel] [PULL v2 for-2.9 07/17] qapi2texi: Fix to actually fail when 'doc-required' is false, Markus Armbruster, 2017/03/22
- [Qemu-devel] [PULL v2 for-2.9 12/17] qapi: Fix string input visitor regression for empty lists, Markus Armbruster, 2017/03/22
- [Qemu-devel] [PULL v2 for-2.9 02/17] keyval: Improve some comments, Markus Armbruster, 2017/03/22
- [Qemu-devel] [PULL v2 for-2.9 03/17] test-keyval: Cover alternate and 'any' type, Markus Armbruster, 2017/03/22
- [Qemu-devel] [PULL v2 for-2.9 14/17] test-qobject-input-visitor: Cover visit_type_uint64(), Markus Armbruster, 2017/03/22
- [Qemu-devel] [PULL v2 for-2.9 08/17] qapi: Drop unused QAPIDoc member optional, Markus Armbruster, 2017/03/22
- [Qemu-devel] [PULL v2 for-2.9 01/17] test-keyval: Tweaks to improve list coverage, Markus Armbruster, 2017/03/22
- [Qemu-devel] [PULL v2 for-2.9 04/17] keyval: Document issues with 'any' and alternate types, Markus Armbruster, 2017/03/22
- [Qemu-devel] [PULL v2 for-2.9 06/17] qapi: Drop excessive Make dependencies on qapi2texi.py, Markus Armbruster, 2017/03/22
- [Qemu-devel] [PULL v2 for-2.9 13/17] Revert "hostmem: fix QEMU crash by 'info memdev'",
Markus Armbruster <=
- [Qemu-devel] [PULL v2 for-2.9 17/17] qapi: Fix QemuOpts visitor regression on unvisited input, Markus Armbruster, 2017/03/22
- [Qemu-devel] [PULL v2 for-2.9 16/17] qom: Avoid unvisited 'id'/'qom-type' in user_creatable_add_opts, Markus Armbruster, 2017/03/22
- [Qemu-devel] [PULL v2 for-2.9 10/17] tests/qapi-schema: Systematic positive doc comment tests, Markus Armbruster, 2017/03/22
- [Qemu-devel] [PULL v2 for-2.9 15/17] tests: Expose regression in QemuOpts visitor, Markus Armbruster, 2017/03/22
- [Qemu-devel] [PULL v2 for-2.9 05/17] MAINTAINERS: Add myself for files I touched recently, Markus Armbruster, 2017/03/22