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Received: from authenticated user by stravinsky.debian.org with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.96) (envelope-from ) id 1wHNDS-005YR3-2h; Mon, 27 Apr 2026 14:45:43 +0000 Date: Mon, 27 Apr 2026 07:45:37 -0700 From: Breno Leitao To: Lance Yang Cc: linmiaohe@huawei.com, nao.horiguchi@gmail.com, akpm@linux-foundation.org, corbet@lwn.net, skhan@linuxfoundation.org, david@kernel.org, ljs@kernel.org, Liam.Howlett@oracle.com, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, shuah@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, kernel-team@meta.com Subject: Re: [PATCH v5 1/4] mm/memory-failure: report MF_MSG_KERNEL for reserved pages Message-ID: References: <20260424-ecc_panic-v5-1-a35f4b50425c@debian.org> <20260427123330.92847-1-lance.yang@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260427123330.92847-1-lance.yang@linux.dev> X-Debian-User: leitao X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 0136E10000E X-Rspam-User: X-Stat-Signature: 4h6bw34ha6zoat6ipfrhsuwps77x49b1 X-HE-Tag: 1777301163-861844 X-HE-Meta: U2FsdGVkX1+UJTuIzgRBvYBCtYm54hLLD6xOsW02Tc9K3b7hcVp/00J7fHR5GOQMONzb07NNpsBktJ1bc1XLOJIOacQYvzTrwafI7MEzL3l5EP+peVsu19jron1wf/V10+IxRzj0p76pEK7gBelLucOw0j+HCbSuQIpoa+mT7Smq6fsoQg8HEbF+E2uqUPg3PrNTe+gPU2C7h87j4BHgeVTj3BtM7NCTprDdV+PnmvJu22CnnQeTbsc8DgPnGnobXr1prNLR58vfI+CqWPnqufLpaNZaB8XLo+oBVUxJ+7Ren2wdaT1KEq/1sp7t9s9x2sDSQvmDmLTtHXqZAOQeReVy1QWJo/9Gih37XgdKDD1ipvU5+O0mdSuFjIWJ6bDkul5BcXl3Us9eyOuSFTApsNjGI2ryofO6P20FhUnEPYzzFoF8JrH9+f0QTG/5BI4WTAQ38xizEInmhoq7YVVycLJ73RR+1sJAHReRoah4ztcqxutdVn4QZc3z34soKDmdo4tlnx26DeGAkhZpVGCuE8oVIax4XhghQu7PVaAivN5HW8CeR1qTNDIP2o/D0EWPqANdZmDTvBpwVRtb3raorxgXFTFv7uUxzFfXVlb5Ov4zJN1TXFas9xO9oHAo1Bpuv1y5hbgDQFiVjD/NQmZrpY35DijVR3uQOtR0HPixCqehk4aw1AxMEzUiZxWarcB7LowK9Z9JzmTzZ6/aalWzGNoz2U46KWCtToRHHQbS35jkv9kZowTYDNZKM89NKmRGUy22yupjgnGpTHW7K5cvL57/vAjCxS9pRzvDE6tXnWyrjoO8c9XuQGDKsxxoG7ibpPrP+m5j/znWYWgLU0YApktNJOoLguPoPPn/y9Mmuxr/Rfc3MG7Mzg5D/vgooWOUjDhr4OP18Ge1aizAagGnN5T9ABM6nMyVrJSwXdOtBL9mP5+RDuG3ule2R9WI6s036tmstmfLeVX5SEUFZa5 CLBf6QYe lH0CGU3+aquT0oNcpnc6YEdw76yewRHHaH05jUYUXWsmN6qfefkxgFUgE2DNheMEXL3PcIuxsBvnpbysPbyUe9GR940SHvGYgwVUTHpzMxRgKCQQu2jagMt+cd1wOS13Gbwzy6F4QsZ8a9UHPsMer44P5Ca4puNIGpk+UyxkNGSRhqtOSg0Vn87kUmYBwdwUp7bDBMqD7H3kE9KtTiAJt44Vo1TL7YlvSQGsXYS6+OOaIjs7L257ZWVz5fAdx7RN4d2TPAnfMXcZzv1u6KuzkBRc3aq9nq+Jk/WiyX3Mt0Jcyv6lEfBdRDB35wl+sZFSe3t/jz66b95a22pYnEb7hBlbcJJHJSUxOoh3Q2Onyg6UnEug= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Apr 27, 2026 at 08:33:30PM +0800, Lance Yang wrote: > > On Fri, Apr 24, 2026 at 05:23:59AM -0700, Breno Leitao wrote: > >When get_hwpoison_page() returns a negative value, distinguish > >reserved pages from other failure cases by reporting MF_MSG_KERNEL > >instead of MF_MSG_GET_HWPOISON. Reserved pages belong to the kernel > >and should be classified accordingly for proper handling. > > > >Acked-by: Miaohe Lin > >Signed-off-by: Breno Leitao > >--- > > mm/memory-failure.c | 11 ++++++++++- > > 1 file changed, 10 insertions(+), 1 deletion(-) > > > >diff --git a/mm/memory-failure.c b/mm/memory-failure.c > >index ee42d43613097..7b67e43dafbd1 100644 > >--- a/mm/memory-failure.c > >+++ b/mm/memory-failure.c > >@@ -2432,7 +2432,16 @@ int memory_failure(unsigned long pfn, int flags) > > } > > goto unlock_mutex; > > } else if (res < 0) { > >- res = action_result(pfn, MF_MSG_GET_HWPOISON, MF_IGNORED); > >+ /* > >+ * PageReserved is stable here: reserved pages have > >+ * PG_reserved set at boot or by drivers and are never > >+ * freed through the page allocator. > >+ */ > > Not necessarily. PG_reserved is not a permanent lifetime property for > every page that has carried it. > > page-flags.h says early reserved pages may later have PG_reserved > cleared and then be given to the page allocator :) > > At least some drivers also clear PG_reserved when releasing pages they > marked reserved. > > Would it be clearer to say that pages with PG_reserved set are not > currently managed by the page allocator, rather than saying reserved > pages are never freed through the page allocator? Would a comment like the following look better? /* * Pages with PG_reserved set are not currently managed by the * page allocator (memblock-reserved memory, driver reservations, * etc.), so classify them as kernel-owned for reporting. */ if (PageReserved(p)) res = action_result(pfn, MF_MSG_KERNEL, MF_IGNORED); Thanks for the review, --breno