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b=qgAwqqmFtRwRcKbqxM7zNQkWcn1MnzslfW5GUXgQ1GEFdzKw5HNEgLV/6kbFlpz3O ZmiQ9G56PMkL1L6kijRDjNicm1JmnMpjkeB+WGWY1IwUGigTOR2+hgMM7+lqB0Vuup qc0V0Xe+NU+0sQGhzOzseRtkjj3MCZ5g66jBN3PTVfdZhZ3iu+TC33SLTc9iKcXYyn m3ihTCJFqzTWeNlALhBrlgX1bLmh0KVF9xX2NIjyXVB3gc9T2wVW0jW+V59coxPe58 6pTvT4/t0PB14vN6g/mLGT06xebpuYHyrhoqQlSg48FyCcOYbV2R2YVfva0/WCCih+ c1M2pp4dGrvQA== Message-ID: <37b48d94-9576-4529-8576-d4ed615d4768@kernel.org> Date: Thu, 19 Mar 2026 11:59:57 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [syzbot] [mm?] kernel BUG in collapse_scan_file To: "Lorenzo Stoakes (Oracle)" Cc: Lance Yang , syzbot , willy@infradead.org, baolin.wang@linux.alibaba.com, npache@redhat.com, linux-mm@kvack.org, baohua@kernel.org, ryan.roberts@arm.com, syzkaller-bugs@googlegroups.com, dev.jain@arm.com, ziy@nvidia.com, linux-kernel@vger.kernel.org, Liam.Howlett@oracle.com, akpm@linux-foundation.org References: <69bba3c0.050a0220.227207.002b.GAE@google.com> <10e5f1d6-077d-4783-aa16-6c8b98cb9e74@lucifer.local> <8ab10631-4672-4196-b32e-7c5a01707424@kernel.org> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 479C5C000C X-Stat-Signature: pqs4hmimfdnaqki5bfuc3xcp4tnioas5 X-Rspam-User: X-Rspamd-Server: rspam06 X-HE-Tag: 1773918004-750377 X-HE-Meta: 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 vYT25FJf AaOB0EvNWSXOSJimfYs+G5bM1Mjx5RE2KNT9+ShlnScTM5TB/sPe40cyxSe0fGpXDG7CG024H1nVIL5Q5eIwaPNxN6YUs/ZoQBqhbGkLdfYGmSaDDvgXToBc+8morj5FzmI4/LgkQpgGCfsDSOwCIv591N7kaO5zh/AUiMTfPIQ2gd28MKnJG9cjNgDYMwBt4LxjXdugc6zTatgGmNXBLZnK8k1Vc0n5RozCM6krOCvQM5OIFLyDQsuKj5/0lfAg93si7/9E26QIRbOIQnJlkxHOiUddHfJJ27P5p3Vz+BT64XL7eq1YnIBJAnfDcGvk9LISlOvmY7i4uslSoBzS4ciPVunzRX/V/rrF8tTEmCIug9qwl8aPcA5P1j3rq2emrTDQ20iIkqKUoA4l9Yd2aBF5dhfKtbWPSx1xcrQ9CHt0c0JooqaToph5WfAwvdmGBEZ6SpEJgG9Pd58NuYOPGcj9frw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: > We shouldn't, really, be just ignoring splatting kernels like that. At least > that's my personal point of view on it. Yes, we shouldn't. > > But anyway I really don't have the time or energy to try to track this down or > push on this further. The problem I'm having is that reverting the commit might hide a real problem, and understanding weather there is a real problem requires ... real work. Willy said "It *might* still be safe in this instance; I'll look at this carefully for a bit and decide how best to fix it." That likely didn't happen. Later he said: "But this is a long and complicated function (over 400 lines!) and I don't know if fixing this one way or the other would serve to make other bugs more likely or expose some future problem to the debugging code." with "This isn't the kind of thing where you can just jump in with a one line patch and actually be helpful, sorry." So I am clueless if there is a real problem there or whether it's just a false positive. And whether (if it's a real problem) the simple fix would actually be a good temporary fix ("make other bugs more likely"). I can try finding some time to look into that, but pagecache code is not particularly the code I'm familiar with ... -- Cheers, David