From: Jens Axboe <axboe@kernel.dk>
To: James Bottomley <James.Bottomley@HansenPartnership.com>,
Arnd Bergmann <arnd@arndb.de>,
Andrew Morton <akpm@linux-foundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
Hannes Reinecke <hare@suse.com>,
Matthew Wilcox <willy@infradead.org>,
David Hildenbrand <david@redhat.com>,
Nikolay Borisov <nborisov@suse.com>,
linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] io_uring: fix big-endian compat signal mask handling
Date: Mon, 25 Mar 2019 10:23:33 -0600 [thread overview]
Message-ID: <4c77d293-8eb9-01aa-27f8-7f320082e182@kernel.dk> (raw)
In-Reply-To: <1553530766.2955.51.camel@HansenPartnership.com>
On 3/25/19 10:19 AM, James Bottomley wrote:
> On Mon, 2019-03-25 at 15:34 +0100, Arnd Bergmann wrote:
>> On big-endian architectures, the signal masks are differnet
>> between 32-bit and 64-bit tasks, so we have to use a different
>> function for reading them from user space.
>>
>> io_cqring_wait() initially got this wrong, and always interprets
>> this as a native structure. This is ok on x86 and most arm64,
>> but not on s390, ppc64be, mips64be, sparc64 and parisc.
>>
>> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
>> ---
>> fs/io_uring.c | 10 +++++++++-
>> 1 file changed, 9 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/io_uring.c b/fs/io_uring.c
>> index 6aaa30580a2b..8f48d29abf76 100644
>> --- a/fs/io_uring.c
>> +++ b/fs/io_uring.c
>> @@ -1968,7 +1968,15 @@ static int io_cqring_wait(struct io_ring_ctx
>> *ctx, int min_events,
>> return 0;
>>
>> if (sig) {
>> - ret = set_user_sigmask(sig, &ksigmask, &sigsaved,
>> sigsz);
>> +#ifdef CONFIG_COMPAT
>> + if (in_compat_syscall())
>> + ret = set_compat_user_sigmask((const
>> compat_sigset_t __user *)sig,
>> + &ksigmask,
>> &sigsaved, sigsz);
>> + else
>> +#endif
>
> This looks a bit suboptimal: shouldn't in_compat_syscall() be hard
> coded to return 0 if CONFIG_COMPAT isn't defined? That way the
> compiler can do the correct optimization and we don't have to litter
> #ifdefs and worry about undefined variables and other things.
That requires the types to be valid for !CONFIG_COMPAT, as well as the
sigmask helper.
--
Jens Axboe
next prev parent reply other threads:[~2019-03-25 16:23 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-25 14:34 [PATCH 1/2] io_uring: fix big-endian compat signal mask handling Arnd Bergmann
2019-03-25 14:47 ` [PATCH 2/2] arch: add pidfd and io_uring syscalls everywhere Arnd Bergmann
2019-03-25 17:37 ` Paul Burton
2019-03-26 8:40 ` Arnd Bergmann
2019-03-30 9:42 ` Heiko Carstens
2019-03-31 9:47 ` Michael Ellerman
2019-03-31 16:28 ` Arnd Bergmann
2019-04-03 1:19 ` Michael Ellerman
2019-04-01 8:19 ` Geert Uytterhoeven
2019-04-03 2:47 ` Michael Ellerman
2019-04-03 11:11 ` Will Deacon
2019-04-03 13:49 ` Jens Axboe
2019-04-03 15:19 ` Will Deacon
2019-04-03 15:39 ` Jens Axboe
2019-04-03 15:49 ` Will Deacon
2019-04-03 15:51 ` Jens Axboe
2019-04-04 6:08 ` Michael Ellerman
2019-03-25 16:05 ` [PATCH 1/2] io_uring: fix big-endian compat signal mask handling Jens Axboe
2019-03-25 16:11 ` Arnd Bergmann
2019-03-25 16:15 ` Jens Axboe
2019-03-25 16:19 ` James Bottomley
2019-03-25 16:23 ` Jens Axboe [this message]
2019-03-25 16:24 ` Arnd Bergmann
2019-03-26 0:13 ` James Bottomley
2019-03-26 8:35 ` Arnd Bergmann
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