The patch titled
Subject: ipc/mqueue: correct mq_attr_ok test
has been added to the -mm tree. Its filename is
ipc-mqueue-correct-mq_attr_ok-test.patch
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From: Doug Ledford <dledford@xxxxxxxxxx>
Subject: ipc/mqueue: correct mq_attr_ok test
While working on the other parts of the mqueue stuff, I noticed that the
calculation for overflow in mq_attr_ok didn't actually match reality (this
is especially true since my last patch which changed how we account memory
slightly).
In particular, we used to test for overflow using:
msgs * msgsize + msgs * sizeof(struct msg_msg *)
That was never really correct because each message we allocate via
load_msg() is actually a struct msg_msg followed by the data for the
message (and if struct msg_msg + data exceeds PAGE_SIZE we end up
allocating struct msg_msgseg structs too, but accounting for them would
get really tedious, so let's ignore those...they're only a pointer in size
anyway). This patch updates the calculation to be more accurate in
regards to maximum possible memory consumption by the mqueue.
Signed-off-by: Doug Ledford <dledford@xxxxxxxxxx>
Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Cc: Manfred Spraul <manfred@xxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
ipc/mqueue.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff -puN ipc/mqueue.c~ipc-mqueue-correct-mq_attr_ok-test ipc/mqueue.c
--- a/ipc/mqueue.c~ipc-mqueue-correct-mq_attr_ok-test
+++ a/ipc/mqueue.c
@@ -671,6 +671,8 @@ static void remove_notification(struct m
static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr)
{
+ int mq_treesize;
+
if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
return 0;
if (capable(CAP_SYS_RESOURCE)) {
@@ -685,8 +687,11 @@ static int mq_attr_ok(struct ipc_namespa
/* check for overflow */
if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
return 0;
- if ((unsigned long)(attr->mq_maxmsg * (attr->mq_msgsize
- + sizeof (struct msg_msg *))) <
+ mq_treesize = attr->mq_maxmsg * sizeof(struct msg_msg) +
+ min_t(unsigned int, attr->mq_maxmsg, MQ_PRIO_MAX) *
+ sizeof(struct posix_msg_tree_node);
+ if ((unsigned long)(attr->mq_maxmsg * attr->mq_msgsize +
+ mq_treesize) <
(unsigned long)(attr->mq_maxmsg * attr->mq_msgsize))
return 0;
return 1;
_
Subject: Subject: ipc/mqueue: correct mq_attr_ok test
Patches currently in -mm which might be from dledford@xxxxxxxxxx are
ipc-mqueue-cleanup-definition-names-and-locations.patch
ipc-mqueue-switch-back-to-using-non-max-values-on-create.patch
ipc-mqueue-enforce-hard-limits.patch
ipc-mqueue-update-maximums-for-the-mqueue-subsystem.patch
ipc-mqueue-update-maximums-for-the-mqueue-subsystem-fix.patch
mqueue-revert-bump-up-dflt_max.patch
mqueue-dont-use-kmalloc-with-kmalloc_max_size.patch
mqueue-separate-mqueue-default-value-from-maximum-value-v2.patch
selftests-add-mq_open_tests.patch
ipc-mqueue-improve-performance-of-send-recv.patch
ipc-mqueue-improve-performance-of-send-recv-fix.patch
ipc-mqueue-correct-mq_attr_ok-test.patch
ipc-mqueue-correct-mq_attr_ok-test-fix.patch
ipc-mqueue-strengthen-checks-on-mqueue-creation.patch
tools-selftests-add-mq_perf_tests.patch
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