Re: mmotm 2020-05-13-20-30 uploaded (objtool warnings)

2020-05-29 Thread Al Viro
On Fri, May 29, 2020 at 09:08:56PM +0100, Al Viro wrote: > On Fri, May 29, 2020 at 12:31:04PM -0700, Linus Torvalds wrote: > > On Fri, May 29, 2020 at 9:50 AM Josh Poimboeuf wrote: > > > > > > From staring at the asm I think the generated code is correct, it's just > > > that the nested likelys wi

Re: mmotm 2020-05-13-20-30 uploaded (objtool warnings)

2020-05-29 Thread Al Viro
On Fri, May 29, 2020 at 12:31:04PM -0700, Linus Torvalds wrote: > On Fri, May 29, 2020 at 9:50 AM Josh Poimboeuf wrote: > > > > From staring at the asm I think the generated code is correct, it's just > > that the nested likelys with ftrace profiling cause GCC to converge the > > error/success pat

Re: mmotm 2020-05-13-20-30 uploaded (objtool warnings)

2020-05-29 Thread Linus Torvalds
On Fri, May 29, 2020 at 9:50 AM Josh Poimboeuf wrote: > > From staring at the asm I think the generated code is correct, it's just > that the nested likelys with ftrace profiling cause GCC to converge the > error/success paths. But objtool doesn't do register value tracking so > it's not smart en

Re: mmotm 2020-05-13-20-30 uploaded (objtool warnings)

2020-05-29 Thread Peter Zijlstra
On Fri, May 29, 2020 at 11:50:11AM -0500, Josh Poimboeuf wrote: > The nested likelys seem like overkill anyway -- user_access_begin() is > __always_inline and it already has unlikely(), which should be > propagated. > > So just remove the outer likelys? That fixes it. Ack! > diff --git a/arch/x8

Re: mmotm 2020-05-13-20-30 uploaded (objtool warnings)

2020-05-29 Thread Josh Poimboeuf
On Fri, May 29, 2020 at 06:12:53PM +0200, Peter Zijlstra wrote: > On Fri, May 29, 2020 at 11:05:14AM -0500, Josh Poimboeuf wrote: > > > It looks to me like GCC is doing the right thing. That likely() > > translates to: > > > > # define likely(x) (__branch_check__(x, 1, __builtin_constant_p(x)))

Re: mmotm 2020-05-13-20-30 uploaded (objtool warnings)

2020-05-29 Thread Peter Zijlstra
On Fri, May 29, 2020 at 11:05:14AM -0500, Josh Poimboeuf wrote: > It looks to me like GCC is doing the right thing. That likely() > translates to: > > # define likely(x) (__branch_check__(x, 1, __builtin_constant_p(x))) > > which becomes: > > #define __branch_check__(x, expect, is_constant)

Re: mmotm 2020-05-13-20-30 uploaded (objtool warnings)

2020-05-29 Thread Josh Poimboeuf
On Fri, May 29, 2020 at 05:33:36PM +0200, Peter Zijlstra wrote: > On Fri, May 29, 2020 at 04:53:25PM +0200, Peter Zijlstra wrote: > > On Fri, May 29, 2020 at 04:35:56PM +0200, Peter Zijlstra wrote: > > > *groan*, this is one of those CONFIG_PROFILE_ALL_BRANCHES builds. If I > > disable that it goe

Re: mmotm 2020-05-13-20-30 uploaded (objtool warnings)

2020-05-29 Thread Peter Zijlstra
On Fri, May 29, 2020 at 04:53:25PM +0200, Peter Zijlstra wrote: > On Fri, May 29, 2020 at 04:35:56PM +0200, Peter Zijlstra wrote: > *groan*, this is one of those CONFIG_PROFILE_ALL_BRANCHES builds. If I > disable that it goes away. > > Still trying to untangle the mess it generated, but on first

Re: mmotm 2020-05-13-20-30 uploaded (objtool warnings)

2020-05-29 Thread Peter Zijlstra
On Fri, May 29, 2020 at 04:35:56PM +0200, Peter Zijlstra wrote: > On Fri, May 29, 2020 at 03:57:51PM +0200, Christoph Hellwig wrote: > > On Thu, May 28, 2020 at 07:20:05PM +0200, Peter Zijlstra wrote: > > > > on x86_64: > > > > > > > > arch/x86/lib/csum-wrappers_64.o: warning: objtool: > > > > cs

Re: mmotm 2020-05-13-20-30 uploaded (objtool warnings)

2020-05-29 Thread Peter Zijlstra
On Fri, May 29, 2020 at 03:57:51PM +0200, Christoph Hellwig wrote: > On Thu, May 28, 2020 at 07:20:05PM +0200, Peter Zijlstra wrote: > > > on x86_64: > > > > > > arch/x86/lib/csum-wrappers_64.o: warning: objtool: > > > csum_and_copy_from_user()+0x2a4: call to memset() with UACCESS enabled > > > a

Re: mmotm 2020-05-13-20-30 uploaded (objtool warnings)

2020-05-29 Thread Christoph Hellwig
On Thu, May 28, 2020 at 07:20:05PM +0200, Peter Zijlstra wrote: > > on x86_64: > > > > arch/x86/lib/csum-wrappers_64.o: warning: objtool: > > csum_and_copy_from_user()+0x2a4: call to memset() with UACCESS enabled > > arch/x86/lib/csum-wrappers_64.o: warning: objtool: > > csum_and_copy_to_user()+

Re: mmotm 2020-05-13-20-30 uploaded (objtool warnings)

2020-05-28 Thread Peter Zijlstra
On Thu, May 14, 2020 at 08:32:22AM -0700, Randy Dunlap wrote: > On 5/13/20 8:31 PM, Andrew Morton wrote: > > The mm-of-the-moment snapshot 2020-05-13-20-30 has been uploaded to > > > >http://www.ozlabs.org/~akpm/mmotm/ > > > > mmotm-readme.txt says > > > > README for mm-of-the-moment: > > >

Re: mmotm 2020-05-13-20-30 uploaded (objtool warnings)

2020-05-28 Thread Josh Poimboeuf
On Thu, May 28, 2020 at 10:54:09AM -0500, Josh Poimboeuf wrote: > On Thu, May 14, 2020 at 08:32:22AM -0700, Randy Dunlap wrote: > > On 5/13/20 8:31 PM, Andrew Morton wrote: > > > The mm-of-the-moment snapshot 2020-05-13-20-30 has been uploaded to > > > > > >http://www.ozlabs.org/~akpm/mmotm/ >

Re: mmotm 2020-05-13-20-30 uploaded (objtool warnings)

2020-05-28 Thread Josh Poimboeuf
On Thu, May 14, 2020 at 08:32:22AM -0700, Randy Dunlap wrote: > On 5/13/20 8:31 PM, Andrew Morton wrote: > > The mm-of-the-moment snapshot 2020-05-13-20-30 has been uploaded to > > > >http://www.ozlabs.org/~akpm/mmotm/ > > > > mmotm-readme.txt says > > > > README for mm-of-the-moment: > > >

Re: mmotm 2020-05-13-20-30 uploaded (objtool warnings)

2020-05-14 Thread Randy Dunlap
On 5/14/20 8:32 AM, Randy Dunlap wrote: > On 5/13/20 8:31 PM, Andrew Morton wrote: >> The mm-of-the-moment snapshot 2020-05-13-20-30 has been uploaded to >> >>http://www.ozlabs.org/~akpm/mmotm/ >> >> mmotm-readme.txt says >> >> README for mm-of-the-moment: >> >> http://www.ozlabs.org/~akpm/mmot

Re: mmotm 2020-05-13-20-30 uploaded (objtool warnings)

2020-05-14 Thread Randy Dunlap
On 5/13/20 8:31 PM, Andrew Morton wrote: > The mm-of-the-moment snapshot 2020-05-13-20-30 has been uploaded to > >http://www.ozlabs.org/~akpm/mmotm/ > > mmotm-readme.txt says > > README for mm-of-the-moment: > > http://www.ozlabs.org/~akpm/mmotm/ > > This is a snapshot of my -mm patch queu