Regression on linux-next (next-20250321)

[Borah, Chaitanya Kumar]

> -----Original Message-----
> From: Josh Poimboeuf <jpoimboe at kernel.org>
> Sent: Thursday, March 27, 2025 11:09 AM
> To: Jason Gunthorpe <jgg at nvidia.com>
> Cc: Nicolin Chen <nicolinc at nvidia.com>; Peter Zijlstra
> <peterz at infradead.org>; Borah, Chaitanya Kumar
> <chaitanya.kumar.borah at intel.com>; iommu at lists.linux.dev; intel-
> gfx at lists.freedesktop.org; intel-xe at lists.freedesktop.org; Kurmi, Suresh
> Kumar <suresh.kumar.kurmi at intel.com>; Saarinen, Jani
> <jani.saarinen at intel.com>
> Subject: Re: Regression on linux-next (next-20250321)
> 
> On Tue, Mar 25, 2025 at 10:43:17AM -0300, Jason Gunthorpe wrote:
> > On Tue, Mar 25, 2025 at 12:40:16AM -0700, Nicolin Chen wrote:
> > >
> > > On Tue, Mar 25, 2025 at 05:39:39AM +0000, Borah, Chaitanya Kumar
> wrote:
> > > > Hello Nicolin,
> > > >
> > > > Hope you are doing well. I am Chaitanya from the linux graphics team in
> Intel.
> > > >
> > > > This mail is regarding a regression we are seeing in our CI runs[1] on linux-
> next repository.
> > > >
> > > > Since the version next-20250321 [2], we are seeing the following
> > > > regression
> > > >
> > > > `````````````````````````````````````````````````````````````````````````````````
> > > > <4>[    0.226495] Unpatched return thunk in use. This should not
> happen!
> > > > <4>[    0.226502] WARNING: CPU: 0 PID: 1 at
> arch/x86/kernel/cpu/bugs.c:3107 __warn_thunk+0x62/0x70
> > >
> > > Hmm....I wonder why x86 can be affected...
> >
> > I wonder if this is realted to the objtool warning Steven reported:
> >
> > https://lore.kernel.org/linux-
> next/20250321193600.2bfe03bb at canb.auug.o
> > rg.au/
> >
> > vmlinux.o: warning: objtool: iommu_dma_get_msi_page() falls through to
> > next function __iommu_dma_unmap()
> >
> > I have no idea what either error means or how to fix it. AFAICT there
> > is nothing special about this patch to trigger this?
> 
> Yeah, I'm fairly sure the boot warning is related to that objtool warning.  I just
> posted a patch for that:
> 
> 
> https://lore.kernel.org/0c801ae017ec078cacd39f8f0898fc7780535f85.174
> 3053325.git.jpoimboe at kernel.org
> 
> But also, we need to fix objtool to handle that warning more gracefully so it
> doesn't trigger the boot failure.

Thank  you for the change.
We can confirm that this gets rid of the boot failures. Does it land in linux-next soon?

Regards

Chaitanya


> 
> --
> Josh