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Howlett" , "Liam R. Howlett" Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, Breno Leitao , linux-trace-kernel@vger.kernel.org, kernel-team@meta.com X-Mailer: b4 0.16-dev-d5d98 X-Developer-Signature: v=1; a=openpgp-sha256; l=2349; i=leitao@debian.org; h=from:subject:message-id; bh=ScD3PYIZI0a0zheAr9zG3EYnPdJ+1Id9YqVY4Vqhi9M=; b=owEBbQKS/ZANAwAIATWjk5/8eHdtAcsmYgBqFvpbSHPg/Q3Yw/y6hVA3+yUCTI5vOf63OaaDy PBtuXI33n2JAjMEAAEIAB0WIQSshTmm6PRnAspKQ5s1o5Of/Hh3bQUCahb6WwAKCRA1o5Of/Hh3 bfXJD/4243i7IKsLyoJqofCvvgKk9Dsh5l+ijiS4/qpYxUtgxCTg9AGQ7dwb6gA1j5ynY2ualvU hueGPfZztKfg/yhB6R0A9SzM8tXHXMRqgicNVspCzCvs7MeKkemykMLcT1oudAxIVxwyjrprib3 SaDs2sTAL3SJA/MRvuTWOOyQiewhmH4vjtlutp9FOHWTfCiO6Zy83C+F4OeQ1827Vspm8ME4eBS HM4ZMPyC9+iv1mQS9djCxHdMpnzLSMg7KW2spA342HL9gP3dnFw4KOM2tVrKDA7rpfptTjnqX5K Idi3cZ9REl08MWzDB+IDTGEdgsO7ATX2g9iIbnfKiRb8TvIIkEcZKi+GhFyI1FvJfXIr2HDeUcD RPC0xxN4mZb5ejFmqdv3tKBwxwo+JUd/RI3NKgXbxoL1qFJYvwEujqb02oyHA2YG9rrvBlCED1a p5hjanYu66vGyfWMYAUDSSrbJGyF3wPn0R8EbB2LcXEJhNAGbaFVqQg4EBE1xVKZANHxAEUo5f5 jqAp6CVyRnBBkn5jcOS5YGUjYoQcuLGjIMD3+fe+oWNBRbsFkbVQWNSp9p+BMLoHz3Vi72bnbIu 1SKWwuvZVfO/swdzfQ5iF/sQiFIWYuYUWQTQAtnczGshWv1wttb0tLuq8OP+WR7cBmIuE4RQ18D UuD/cCh1h76EoYA== X-Developer-Key: i=leitao@debian.org; a=openpgp; fpr=AC8539A6E8F46702CA4A439B35A3939FFC78776D X-Debian-User: leitao X-Stat-Signature: 8rkesmuqiymej11ttcm9ken4qeqnye69 X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: E2C75100014 X-HE-Tag: 1779890808-930353 X-HE-Meta: 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 OgVaMT5I ZoCs3nxrCygY1itV7pH8arwopUUz/sqW5elpa2SkF8cfWHf1is9w40Q7Yq27box+zZtrm6TO5WwOm+BXVF51TUihlw1dvMYgW83LuO0E437E5Mt2gr23K5+qOfOlxxQZAQbauPgxabcH4wFUnquM5t85liDKraYMKd5e5ceqXws6e3BMzMu6GbdGKahwQJEw8Bq/fOOCqAbFfxWNShFwB6ioN5PuJGLf+A0IIk2jfAgc22gPJSBCvf3KO+P+k2oBMqbRt+F+kuyCAmF/U9r+qJMmAn/Zaa7DPgCGjqV49PU1fxoHzJFrhkBc8CnSYZX2N2ibdliNq8Ae7YnLYMgcqpx7SbhTSXcYevrWEyttx/B8g3W62lKDw0RlV9eK87XOFFJdZpXHkaUpcEmt+wJhicqQQGDeSCriSwsfimjcawcEa5eA= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: The previous patch teaches get_any_page() to return -ENOTRECOVERABLE for stable unhandlable kernel pages (PG_reserved, slab, page tables, large-kmalloc). memory_failure() still folds every negative return into MF_MSG_GET_HWPOISON, so callers that want to react to the unrecoverable cases (a panic option, smarter logging) cannot tell them apart from transient page-allocator races. Turn the post-call branch into a switch over the get_hwpoison_page() return code: map -ENOTRECOVERABLE to MF_MSG_KERNEL and any other negative return to MF_MSG_GET_HWPOISON. case 0 keeps the existing free-buddy / kernel-high-order handling and case 1 falls through to the rest of memory_failure() unchanged. The MF_MSG_KERNEL label and tracepoint string are kept as "reserved kernel page" to avoid breaking userspace tools that match on those literals; the enum value still adequately tags the failure even though it now also covers slab, page tables and large-kmalloc pages. Suggested-by: David Hildenbrand Signed-off-by: Breno Leitao --- mm/memory-failure.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 8f63bdfeff8f..14c0a958638c 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -2426,7 +2426,8 @@ int memory_failure(unsigned long pfn, int flags) * that may make page_ref_freeze()/page_ref_unfreeze() mismatch. */ res = get_hwpoison_page(p, flags); - if (!res) { + switch (res) { + case 0: if (is_free_buddy_page(p)) { if (take_page_off_buddy(p)) { page_ref_inc(p); @@ -2445,7 +2446,19 @@ int memory_failure(unsigned long pfn, int flags) res = action_result(pfn, MF_MSG_KERNEL_HIGH_ORDER, MF_IGNORED); } goto unlock_mutex; - } else if (res < 0) { + case 1: + /* Got a refcount on a handlable page. */ + break; + case -ENOTRECOVERABLE: + /* + * Stable unhandlable kernel-owned page (PG_reserved, + * slab, page tables, large-kmalloc). + * No recovery possible. + */ + res = action_result(pfn, MF_MSG_KERNEL, MF_IGNORED); + goto unlock_mutex; + default: + /* Transient lifecycle race with the page allocator. */ res = action_result(pfn, MF_MSG_GET_HWPOISON, MF_IGNORED); goto unlock_mutex; } -- 2.54.0