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Date:   Fri, 19 Aug 2022 12:57:09 +0200
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Jean-Philippe Brucker <jean-philippe@linaro.org>
Cc:     RAJESH DASARI <raajeshdasari@gmail.com>, stable@vger.kernel.org,
        linux-kernel@vger.kernel.org, df@google.com
Subject: Re: bpf selftest failed in 5.4.210 kernel
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On Thu, Aug 18, 2022 at 08:55:16AM +0100, Jean-Philippe Brucker wrote:
> On Thu, Aug 18, 2022 at 07:24:03AM +0200, Greg KH wrote:
> > On Wed, Aug 17, 2022 at 09:22:00PM +0300, RAJESH DASARI wrote:
> > > Hi ,
> > > 
> > > We are running bpf selftests on 5.4.210 kernel version and we see that
> > > test case 11 of  test_align failed. Please find the below error.
> > > 
> > > selftests: bpf: test_align
> > > Test  11: pointer variable subtraction ... Failed to find match 16:
> > > R5_w=pkt(id=2,off=0,r=0,umin_value=2,umax_value=1082,var_off=(0x2;
> > > 0xfffffffc)
> > > # func#0 @0
> > > # 0: R1=ctx(id=0,off=0,imm=0) R10=fp0
> > > # 0: (61) r2 = *(u32 *)(r1 +76)
> > > # 1: R1=ctx(id=0,off=0,imm=0) R2_w=pkt(id=0,off=0,r=0,imm=0) R10=fp0
> > > # 1: (61) r3 = *(u32 *)(r1 +80)
> > > 
> > > For complete errors please see the attached file. The same test case
> > > execution was successful in the 5.4.209 version , could you please let
> > > me know any known issue with the recent changes in 5.4.210 and how to
> > > fix these errors.
> > 
> > Can you use 'git bisect' to find the offending commit?
> 
> It probably is 6098562ed9df ("selftests/bpf: Fix "dubious pointer
> arithmetic" test")
> https://lore.kernel.org/all/20220803145005.2385039-6-ovidiu.panait@windriver.com/
> Could you try reverting that?
> 
> The patch didn't have a Fixes: tags, because the bugfix it refers to was
> merged at the same time. That bugfix is upstream commit b02709587ea3
> ("bpf: Fix propagation of 32-bit signed bounds from 64-bit bounds.")
> 
> Since b02709587ea3 was only backported down to 5.10, this fix shouldn't be
> in 5.4. Sorry for not catching this earlier.

Can you send in a revert for this?

thanks,

greg k-h