On Wed, Sep 23, 2020 at 11:01:34AM +0300, Pavel Begunkov wrote:
> > I'm not following why that would be considered a valid option,
> > as that clearly breaks existing users that update from a 32-bit
> > kernel to a 64-bit one.
>
> Do you mean users who move 32-bit binaries (without recompiling) t
On 22/09/2020 12:01, Arnd Bergmann wrote:
> On Tue, Sep 22, 2020 at 9:59 AM Pavel Begunkov wrote:
>> On 22/09/2020 10:23, Arnd Bergmann wrote:
>>> On Tue, Sep 22, 2020 at 8:32 AM Pavel Begunkov
>>> wrote:
On 22/09/2020 03:58, Andy Lutomirski wrote:
> On Mon, Sep 21, 2020 at 5:24 PM Pave
> On Sep 22, 2020, at 2:01 AM, Arnd Bergmann wrote:
>
> On Tue, Sep 22, 2020 at 9:59 AM Pavel Begunkov
> wrote:
>>> On 22/09/2020 10:23, Arnd Bergmann wrote:
>>> On Tue, Sep 22, 2020 at 8:32 AM Pavel Begunkov
>>> wrote:
On 22/09/2020 03:58, Andy Lutomirski wrote:
> On Mon, Sep 21
On Tue, Sep 22, 2020 at 9:59 AM Pavel Begunkov wrote:
> On 22/09/2020 10:23, Arnd Bergmann wrote:
> > On Tue, Sep 22, 2020 at 8:32 AM Pavel Begunkov
> > wrote:
> >> On 22/09/2020 03:58, Andy Lutomirski wrote:
> >>> On Mon, Sep 21, 2020 at 5:24 PM Pavel Begunkov
> >>> wrote:
> >>> I may be look
On 22/09/2020 10:23, Arnd Bergmann wrote:
> On Tue, Sep 22, 2020 at 8:32 AM Pavel Begunkov wrote:
>> On 22/09/2020 03:58, Andy Lutomirski wrote:
>>> On Mon, Sep 21, 2020 at 5:24 PM Pavel Begunkov
>>> wrote:
>>> I may be looking at a different kernel than you, but aren't you
>>> preventing creati
On Tue, Sep 22, 2020 at 8:32 AM Pavel Begunkov wrote:
> On 22/09/2020 03:58, Andy Lutomirski wrote:
> > On Mon, Sep 21, 2020 at 5:24 PM Pavel Begunkov
> > wrote:
> > I may be looking at a different kernel than you, but aren't you
> > preventing creating an io_uring regardless of whether SQPOLL i
On 22/09/2020 03:58, Andy Lutomirski wrote:
> On Mon, Sep 21, 2020 at 5:24 PM Pavel Begunkov wrote:
>>> Ah, so reading /dev/input/event* would suffer from the same issue,
>>> and that one would in fact be broken by your patch in the hypothetical
>>> case that someone tried to use io_ur
On Mon, Sep 21, 2020 at 5:24 PM Pavel Begunkov wrote:
>
>
>
> On 22/09/2020 02:51, Andy Lutomirski wrote:
> > On Mon, Sep 21, 2020 at 9:15 AM Pavel Begunkov
> > wrote:
> >>
> >> On 21/09/2020 19:10, Pavel Begunkov wrote:
> >>> On 20/09/2020 01:22, Andy Lutomirski wrote:
>
> > On Sep 19,
On 22/09/2020 02:51, Andy Lutomirski wrote:
> On Mon, Sep 21, 2020 at 9:15 AM Pavel Begunkov wrote:
>>
>> On 21/09/2020 19:10, Pavel Begunkov wrote:
>>> On 20/09/2020 01:22, Andy Lutomirski wrote:
> On Sep 19, 2020, at 2:16 PM, Arnd Bergmann wrote:
>
> On Sat, Sep 19, 2020 at
On Mon, Sep 21, 2020 at 9:15 AM Pavel Begunkov wrote:
>
> On 21/09/2020 19:10, Pavel Begunkov wrote:
> > On 20/09/2020 01:22, Andy Lutomirski wrote:
> >>
> >>> On Sep 19, 2020, at 2:16 PM, Arnd Bergmann wrote:
> >>>
> >>> On Sat, Sep 19, 2020 at 6:21 PM Andy Lutomirski wrote:
> > On Fri, Se
On 21/09/2020 00:13, David Laight wrote:
> From: Arnd Bergmann
>> Sent: 20 September 2020 21:49
>>
>> On Sun, Sep 20, 2020 at 9:28 PM Andy Lutomirski wrote:
>>> On Sun, Sep 20, 2020 at 12:23 PM Matthew Wilcox wrote:
On Sun, Sep 20, 2020 at 08:10:31PM +0100, Al Viro wrote:
> IMO it's
On 20/09/2020 22:22, Matthew Wilcox wrote:
> On Sun, Sep 20, 2020 at 08:10:31PM +0100, Al Viro wrote:
>> IMO it's much saner to mark those and refuse to touch them from io_uring...
>
> Simpler solution is to remove io_uring from the 32-bit syscall list.
> If you're a 32-bit process, you don't get
On 20/09/2020 18:55, William Kucharski wrote:
> I really like that as it’s self-documenting and anyone debugging it can see
> what is actually being used at a glance.
Also creates special cases for things that few people care about,
and makes it a pain for cross-platform (cross-bitness) developme
On 21/09/2020 19:10, Pavel Begunkov wrote:
> On 20/09/2020 01:22, Andy Lutomirski wrote:
>>
>>> On Sep 19, 2020, at 2:16 PM, Arnd Bergmann wrote:
>>>
>>> On Sat, Sep 19, 2020 at 6:21 PM Andy Lutomirski wrote:
> On Fri, Sep 18, 2020 at 8:16 AM Christoph Hellwig wrote:
> On Fri, Sep 18, 2
On 20/09/2020 01:22, Andy Lutomirski wrote:
>
>> On Sep 19, 2020, at 2:16 PM, Arnd Bergmann wrote:
>>
>> On Sat, Sep 19, 2020 at 6:21 PM Andy Lutomirski wrote:
On Fri, Sep 18, 2020 at 8:16 AM Christoph Hellwig wrote:
On Fri, Sep 18, 2020 at 02:58:22PM +0100, Al Viro wrote:
> Said
On Sun, Sep 20, 2020 at 12:14:49PM -0700, Andy Lutomirski wrote:
> I wonder if this is really quite cast in stone. We could also have
> FMODE_SHITTY_COMPAT and set that when a file like this is *opened* in
> compat mode. Then that particular struct file would be read and
> written using the compa
On Sun, Sep 20, 2020 at 08:22:59PM +0100, Matthew Wilcox wrote:
> On Sun, Sep 20, 2020 at 08:10:31PM +0100, Al Viro wrote:
> > IMO it's much saner to mark those and refuse to touch them from io_uring...
>
> Simpler solution is to remove io_uring from the 32-bit syscall list.
> If you're a 32-bit p
From: Arnd Bergmann
> Sent: 20 September 2020 21:49
>
> On Sun, Sep 20, 2020 at 9:28 PM Andy Lutomirski wrote:
> > On Sun, Sep 20, 2020 at 12:23 PM Matthew Wilcox wrote:
> > >
> > > On Sun, Sep 20, 2020 at 08:10:31PM +0100, Al Viro wrote:
> > > > IMO it's much saner to mark those and refuse to t
On Sun, Sep 20, 2020 at 9:28 PM Andy Lutomirski wrote:
> On Sun, Sep 20, 2020 at 12:23 PM Matthew Wilcox wrote:
> >
> > On Sun, Sep 20, 2020 at 08:10:31PM +0100, Al Viro wrote:
> > > IMO it's much saner to mark those and refuse to touch them from
> > > io_uring...
> >
> > Simpler solution is to
On Sun, Sep 20, 2020 at 12:23 PM Matthew Wilcox wrote:
>
> On Sun, Sep 20, 2020 at 08:10:31PM +0100, Al Viro wrote:
> > IMO it's much saner to mark those and refuse to touch them from io_uring...
>
> Simpler solution is to remove io_uring from the 32-bit syscall list.
> If you're a 32-bit process,
On Sun, Sep 20, 2020 at 08:10:31PM +0100, Al Viro wrote:
> IMO it's much saner to mark those and refuse to touch them from io_uring...
Simpler solution is to remove io_uring from the 32-bit syscall list.
If you're a 32-bit process, you don't get to use io_uring. Would
any real users actually care
On Sun, Sep 20, 2020 at 11:07 AM Al Viro wrote:
>
> On Sun, Sep 20, 2020 at 04:15:10PM +0100, Matthew Wilcox wrote:
> > On Fri, Sep 18, 2020 at 02:45:25PM +0200, Christoph Hellwig wrote:
> > > Add a flag to force processing a syscall as a compat syscall. This is
> > > required so that in_compat_s
On Sun, Sep 20, 2020 at 08:01:59PM +0100, Matthew Wilcox wrote:
> On Sun, Sep 20, 2020 at 07:07:42PM +0100, Al Viro wrote:
> > 2) a few drivers are really fucked in head. They use different
> > *DATA* layouts for reads/writes, depending upon the calling process.
> > IOW, if you fork/exec a 32b
On Sun, Sep 20, 2020 at 07:07:42PM +0100, Al Viro wrote:
> 2) a few drivers are really fucked in head. They use different
> *DATA* layouts for reads/writes, depending upon the calling process.
> IOW, if you fork/exec a 32bit binary and your stdin is one of those,
> reads from stdin in parent
On Sun, Sep 20, 2020 at 07:07:42PM +0100, Al Viro wrote:
> /proc/bus/input/devices (fucked bitmap-to-text representation)
To illustrate the, er, beauty of that stuff:
; cat32 /proc/bus/input/devices >/tmp/a
; cat /proc/bus/input/devices >/tmp/b
; diff -u /tmp/a /tmp/b|grep '^[-+]'
--- /tmp/a
On Sun, Sep 20, 2020 at 09:59:36AM -0700, Andy Lutomirski wrote:
> As one example, look at __sys_setsockopt(). It's called for the
> native and compat versions, and it contains an in_compat_syscall()
> check. (This particularly check looks dubious to me, but that's
> another story.) If this wer
On Sun, Sep 20, 2020 at 04:15:10PM +0100, Matthew Wilcox wrote:
> On Fri, Sep 18, 2020 at 02:45:25PM +0200, Christoph Hellwig wrote:
> > Add a flag to force processing a syscall as a compat syscall. This is
> > required so that in_compat_syscall() works for I/O submitted by io_uring
> > helper thr
On Sat, Sep 19, 2020 at 7:57 PM Al Viro wrote:
>
> On Sat, Sep 19, 2020 at 05:14:41PM -0700, Andy Lutomirski wrote:
>
> > > 2) have you counted the syscalls that do and do not need that?
> >
> > No.
>
> Might be illuminating...
>
> > > 3) how many of those realistically *can* be unified with their
On Sun, Sep 20, 2020 at 5:15 PM Matthew Wilcox wrote:
>
> On Fri, Sep 18, 2020 at 02:45:25PM +0200, Christoph Hellwig wrote:
> > Add a flag to force processing a syscall as a compat syscall. This is
> > required so that in_compat_syscall() works for I/O submitted by io_uring
> > helper threads on
I really like that as it’s self-documenting and anyone debugging it can see
what is actually being used at a glance.
> On Sep 20, 2020, at 09:15, Matthew Wilcox wrote:
>
> On Fri, Sep 18, 2020 at 02:45:25PM +0200, Christoph Hellwig wrote:
>> Add a flag to force processing a syscall as a compat
On Fri, Sep 18, 2020 at 02:45:25PM +0200, Christoph Hellwig wrote:
> Add a flag to force processing a syscall as a compat syscall. This is
> required so that in_compat_syscall() works for I/O submitted by io_uring
> helper threads on behalf of compat syscalls.
Al doesn't like this much, but my su
On Sun, Sep 20, 2020 at 03:55:47PM +0200, Arnd Bergmann wrote:
> On Sun, Sep 20, 2020 at 12:09 AM Al Viro wrote:
> > On Fri, Sep 18, 2020 at 05:16:15PM +0200, Christoph Hellwig wrote:
> > > On Fri, Sep 18, 2020 at 02:58:22PM +0100, Al Viro wrote:
> > > > Said that, why not provide a variant that w
On Sun, Sep 20, 2020 at 12:09 AM Al Viro wrote:
> On Fri, Sep 18, 2020 at 05:16:15PM +0200, Christoph Hellwig wrote:
> > On Fri, Sep 18, 2020 at 02:58:22PM +0100, Al Viro wrote:
> > > Said that, why not provide a variant that would take an explicit
> > > "is it compat" argument and use it there?
On Sat, Sep 19, 2020 at 05:14:41PM -0700, Andy Lutomirski wrote:
> > 2) have you counted the syscalls that do and do not need that?
>
> No.
Might be illuminating...
> > 3) how many of those realistically *can* be unified with their
> > compat counterparts? [hint: ioctl(2) cannot]
>
> There wo
On Sat, Sep 19, 2020 at 4:24 PM Al Viro wrote:
>
> On Sat, Sep 19, 2020 at 03:53:40PM -0700, Andy Lutomirski wrote:
>
> > > It would not be a win - most of the syscalls don't give a damn
> > > about 32bit vs. 64bit...
> >
> > Any reasonable implementation would optimize it out for syscalls that do
On Sat, Sep 19, 2020 at 03:53:40PM -0700, Andy Lutomirski wrote:
> > It would not be a win - most of the syscalls don't give a damn
> > about 32bit vs. 64bit...
>
> Any reasonable implementation would optimize it out for syscalls that don’t
> care. Or it could be explicit:
>
> DEFINE_MULTIARCH
> On Sep 19, 2020, at 3:41 PM, Al Viro wrote:
>
> On Sat, Sep 19, 2020 at 03:23:54PM -0700, Andy Lutomirski wrote:
>>
On Sep 19, 2020, at 3:09 PM, Al Viro wrote:
>>>
>>> On Fri, Sep 18, 2020 at 05:16:15PM +0200, Christoph Hellwig wrote:
> On Fri, Sep 18, 2020 at 02:58:22PM +0100,
On Sat, Sep 19, 2020 at 03:23:54PM -0700, Andy Lutomirski wrote:
>
> > On Sep 19, 2020, at 3:09 PM, Al Viro wrote:
> >
> > On Fri, Sep 18, 2020 at 05:16:15PM +0200, Christoph Hellwig wrote:
> >>> On Fri, Sep 18, 2020 at 02:58:22PM +0100, Al Viro wrote:
> >>> Said that, why not provide a variant
> On Sep 19, 2020, at 3:09 PM, Al Viro wrote:
>
> On Fri, Sep 18, 2020 at 05:16:15PM +0200, Christoph Hellwig wrote:
>>> On Fri, Sep 18, 2020 at 02:58:22PM +0100, Al Viro wrote:
>>> Said that, why not provide a variant that would take an explicit
>>> "is it compat" argument and use it there?
> On Sep 19, 2020, at 2:16 PM, Arnd Bergmann wrote:
>
> On Sat, Sep 19, 2020 at 6:21 PM Andy Lutomirski wrote:
>>> On Fri, Sep 18, 2020 at 8:16 AM Christoph Hellwig wrote:
>>> On Fri, Sep 18, 2020 at 02:58:22PM +0100, Al Viro wrote:
Said that, why not provide a variant that would take a
On Fri, Sep 18, 2020 at 05:16:15PM +0200, Christoph Hellwig wrote:
> On Fri, Sep 18, 2020 at 02:58:22PM +0100, Al Viro wrote:
> > Said that, why not provide a variant that would take an explicit
> > "is it compat" argument and use it there? And have the normal
> > one pass in_compat_syscall() to t
On Sat, 19 Sep 2020, Arnd Bergmann wrote:
> On Sat, Sep 19, 2020 at 6:21 PM Andy Lutomirski wrote:
> > On Fri, Sep 18, 2020 at 8:16 AM Christoph Hellwig wrote:
> > > On Fri, Sep 18, 2020 at 02:58:22PM +0100, Al Viro wrote:
> > > > Said that, why not provide a variant that would take an explicit
On Sat, Sep 19, 2020 at 6:21 PM Andy Lutomirski wrote:
> On Fri, Sep 18, 2020 at 8:16 AM Christoph Hellwig wrote:
> > On Fri, Sep 18, 2020 at 02:58:22PM +0100, Al Viro wrote:
> > > Said that, why not provide a variant that would take an explicit
> > > "is it compat" argument and use it there? An
On Fri, Sep 18, 2020 at 8:16 AM Christoph Hellwig wrote:
>
> On Fri, Sep 18, 2020 at 02:58:22PM +0100, Al Viro wrote:
> > Said that, why not provide a variant that would take an explicit
> > "is it compat" argument and use it there? And have the normal
> > one pass in_compat_syscall() to that...
From: Al Viro
> Sent: 18 September 2020 14:58
>
> On Fri, Sep 18, 2020 at 03:44:06PM +0200, Christoph Hellwig wrote:
> > On Fri, Sep 18, 2020 at 02:40:12PM +0100, Al Viro wrote:
> > > > /* Vector 0x110 is LINUX_32BIT_SYSCALL_TRAP */
> > > > - return pt_regs_trap_type(current_pt_regs(
On Fri, Sep 18, 2020 at 02:58:22PM +0100, Al Viro wrote:
> Said that, why not provide a variant that would take an explicit
> "is it compat" argument and use it there? And have the normal
> one pass in_compat_syscall() to that...
That would help to not introduce a regression with this series yes.
On Fri, Sep 18, 2020 at 3:44 PM Christoph Hellwig wrote:
>
> On Fri, Sep 18, 2020 at 02:40:12PM +0100, Al Viro wrote:
> > > /* Vector 0x110 is LINUX_32BIT_SYSCALL_TRAP */
> > > - return pt_regs_trap_type(current_pt_regs()) == 0x110;
> > > + return pt_regs_trap_type(current_pt_regs()) == 0x
On Fri, Sep 18, 2020 at 03:44:06PM +0200, Christoph Hellwig wrote:
> On Fri, Sep 18, 2020 at 02:40:12PM +0100, Al Viro wrote:
> > > /* Vector 0x110 is LINUX_32BIT_SYSCALL_TRAP */
> > > - return pt_regs_trap_type(current_pt_regs()) == 0x110;
> > > + return pt_regs_trap_type(current_pt_regs()) == 0
On Fri, Sep 18, 2020 at 02:40:12PM +0100, Al Viro wrote:
> > /* Vector 0x110 is LINUX_32BIT_SYSCALL_TRAP */
> > - return pt_regs_trap_type(current_pt_regs()) == 0x110;
> > + return pt_regs_trap_type(current_pt_regs()) == 0x110 ||
> > + (current->flags & PF_FORCE_COMPAT);
>
> Can'
On Fri, Sep 18, 2020 at 02:45:25PM +0200, Christoph Hellwig wrote:
> Add a flag to force processing a syscall as a compat syscall. This is
> required so that in_compat_syscall() works for I/O submitted by io_uring
> helper threads on behalf of compat syscalls.
>
> Signed-off-by: Christoph Hellwig
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