On Fri, 2022-07-15 at 22:33 +1000, Stephen Rothwell wrote:
> Hi all,
>
> On Fri, 15 Jul 2022 13:52:32 +1000 Stephen Rothwell
> <sfr@xxxxxxxxxxxxxxxx> wrote:
> >
> > After merging the block tree, today's linux-next build (arm
> > multi_v7_defconfig) produced this warning:
> >
> > In file included from include/linux/slab.h:16,
> > from io_uring/net.c:5:
> > io_uring/net.c: In function 'io_recvmsg_multishot_overflow':
> > include/linux/overflow.h:67:22: warning: comparison of distinct
> > pointer types lacks a cast
> > 67 | (void) (&__a == &__b); \
> > | ^~
> > io_uring/net.c:332:13: note: in expansion of macro
> > 'check_add_overflow'
> > 332 | if (check_add_overflow(sizeof(struct
> > io_uring_recvmsg_out),
> > | ^~~~~~~~~~~~~~~~~~
> > include/linux/overflow.h:68:22: warning: comparison of distinct
> > pointer types lacks a cast
> > 68 | (void) (&__a == __d); \
> > | ^~
> > io_uring/net.c:332:13: note: in expansion of macro
> > 'check_add_overflow'
> > 332 | if (check_add_overflow(sizeof(struct
> > io_uring_recvmsg_out),
> > | ^~~~~~~~~~~~~~~~~~
> > include/linux/overflow.h:67:22: warning: comparison of distinct
> > pointer types lacks a cast
> > 67 | (void) (&__a == &__b); \
> > | ^~
> > io_uring/net.c:335:13: note: in expansion of macro
> > 'check_add_overflow'
> > 335 | if (check_add_overflow(hdr, iomsg->controllen,
> > &hdr))
> > | ^~~~~~~~~~~~~~~~~~
> >
> > Introduced by commit
> >
> > a8b38c4ce724 ("io_uring: support multishot in recvmsg")
>
> This became a build failure in my i386 defconfig build. So I have
> applied the following (probably not correct) patch that makes it
> build.
>
Thanks for this. Your patch will probably not cause much damage,
however I have suggested the below patch to io_uring since I noticed
that the current logic was a bit off
Dylan
From: Dylan Yudaken <dylany@xxxxxx>
Date: Fri, 15 Jul 2022 05:55:02 -0700
Subject: [PATCH for-next] io_uring: fix types in
io_recvmsg_multishot_overflow
io_recvmsg_multishot_overflow had incorrect types on non x64 system.
But also it had an unnecessary INT_MAX check, which could just be done
by changing the type of the accumulator to int (also simplifying the
casts).
Reported-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Fixes: a8b38c4ce724 ("io_uring: support multishot in recvmsg")
Signed-off-by: Dylan Yudaken <dylany@xxxxxx>
---
io_uring/net.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/io_uring/net.c b/io_uring/net.c
index 616d5f04cc74..6b7d5f33e642 100644
--- a/io_uring/net.c
+++ b/io_uring/net.c
@@ -327,14 +327,14 @@ int io_send(struct io_kiocb *req, unsigned int
issue_flags)
static bool io_recvmsg_multishot_overflow(struct io_async_msghdr
*iomsg)
{
- unsigned long hdr;
+ int hdr;
- if (check_add_overflow(sizeof(struct io_uring_recvmsg_out),
- (unsigned long)iomsg->namelen, &hdr))
+ if (iomsg->namelen < 0)
return true;
- if (check_add_overflow(hdr, iomsg->controllen, &hdr))
+ if (check_add_overflow((int)sizeof(struct
io_uring_recvmsg_out),
+ iomsg->namelen, &hdr))
return true;
- if (hdr > INT_MAX)
+ if (check_add_overflow(hdr, (int)iomsg->controllen, &hdr))
return true;
return false;
base-commit: a8b38c4ce7240d869c820d457bcd51e452149510
--
2.30.2
