From nobody Sat Jun 13 02:03:57 2026 Received: from stravinsky.debian.org (stravinsky.debian.org [82.195.75.108]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 585FE37475B; Mon, 11 May 2026 15:39:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=82.195.75.108 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778513969; cv=none; b=u1C/NzN8cpdYYXcnWXph7+J0jbiP7XXcGhcRdC1Ap3sfXpnjjI5QHjrQ6S3WtkuVmgqGMEr63qG0KPeEYNJSWDcGkxbKEPGRBS41kEaKUYoOqAeJS0GQLBYFtUvUQfLSwj5453sHWu9+Pjx6VZ3/LncB5pHmwa5+bJWEXJ34Vak= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778513969; c=relaxed/simple; bh=QI/LnjFxb7VYKP9kMjSn/xHKUbboDh93Ly768NA/Sh0=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=O3B3qLlBFREhS7hqZv9wFrVMYimrvjllP4ZnMFMyZe4YoZyjiO61L8yzfIB5HMK2qQY8So0FVX1oAA3u9vScrcavDHA95Avx+cE9fKW/TSO/B1mgHWovdGk/BNzDaUZGlojpdgNN0Xper0P3C5hk2tGoUpApRDJprDbHEy68EIk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=debian.org; spf=pass smtp.mailfrom=debian.org; dkim=pass (2048-bit key) header.d=debian.org header.i=@debian.org header.b=pHF4q8JM; arc=none smtp.client-ip=82.195.75.108 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=debian.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=debian.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=debian.org header.i=@debian.org header.b="pHF4q8JM" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=debian.org; s=smtpauto.stravinsky; h=X-Debian-User:Cc:To:In-Reply-To:References: Message-Id:Content-Transfer-Encoding:Content-Type:MIME-Version:Subject:Date: From:Reply-To:Content-ID:Content-Description; bh=b69sgv2dXzpZgJDqciacSImGKfghtkSEKpreyIG4ANY=; b=pHF4q8JMOvrjEpRpwvdcA/Y0AJ bmSwsdg9aFx2wApYypxub3xgo7pX1pwsntjBMS+3qBBDL4jcJlUirPrArj1scXnVrYnhBDrVV/4nb qSoIA8e02BXn1wB3VwCB+Xop+/dS2GDOjlSUezrzHYlfluEkb5JTaURHKTEL1zrCihS+FuLYSLwNl Z9oJrgzH/+GsyWuKIImkgvIpbN1ZLRnMNQt54EO1ukZSM3MmUPAcq4IATUW9NJGMKhTORPWzZ3Uiv uU3jDYbqiIOePo8Bs7o5aZTb8aqRRjo9yoO7Q0qyKB4sFh1CoZrAveaReS95ZkRFwGExkpn8FJlH6 NWCrLkgA==; 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 1wMSj7-001hV4-0s; Mon, 11 May 2026 15:39:25 +0000 From: Breno Leitao Date: Mon, 11 May 2026 08:38:35 -0700 Subject: [PATCH v6 1/4] mm/memory-failure: report MF_MSG_KERNEL for reserved pages Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260511-ecc_panic-v6-1-183012ba7d4b@debian.org> References: <20260511-ecc_panic-v6-0-183012ba7d4b@debian.org> In-Reply-To: <20260511-ecc_panic-v6-0-183012ba7d4b@debian.org> To: Miaohe Lin , Naoya Horiguchi , Andrew Morton , Jonathan Corbet , Shuah Khan , David Hildenbrand , Lorenzo Stoakes , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Shuah Khan , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , "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, Lance Yang X-Mailer: b4 0.16-dev-d5d98 X-Developer-Signature: v=1; a=openpgp-sha256; l=2532; i=leitao@debian.org; h=from:subject:message-id; bh=QI/LnjFxb7VYKP9kMjSn/xHKUbboDh93Ly768NA/Sh0=; b=owEBbQKS/ZANAwAIATWjk5/8eHdtAcsmYgBqAfggio+Z39e2w7EmkUhdYSq8j8L3EAJysjNpB FODq8lSTPSJAjMEAAEIAB0WIQSshTmm6PRnAspKQ5s1o5Of/Hh3bQUCagH4IAAKCRA1o5Of/Hh3 bWOQEACiBsHHaTmf6qkAQgpaa6psj5wgPRGrykdRJebZdVweBu/5FladzS3IRVJ1nn8r4sIv237 /Kn8R5feYMah7QSWj4s5mmO5v2efGVHq3yxkl9Zomn5uK533a5eGM9EfvCA2ENMpBUgYQcb65Qz E3zpItx14T5EcEMPhQec4ga2godHp86qBhe3fY1jp7mSOsjFvDsBbdbP+o4dmgPUTXrfqmz7O5x Qt3nk/3aBCGUW4CdNyviQy/YwaRWkcNslxlXyX26EAsxAalB7r88pShp21mNej+Arduktkk4OfO UMMnI+R6IlJwBGZfqAdWpCjNfknHSZ0O4BvEWLZo/Kq0IENtGmuL2taWPNcybeHd0GuTKch49Sv qtLwyVy/yDbgFgCy3/cLYOtrFQCiT9PkjFjV+gTHdwLBRpwTuSF45L4OTBZbxhvub687mIpZ/06 paXT5WGuj27VbrH97RZR+HS1WBqI0WZdXlOo8wxxZvHW0llRpYW4TY7NLqnf3IYk1qFcwQ8CpUb lAPUyne3lUEXvO/fZb3qvhDbR3nZPrqHBp9mgz3CqI1RUlbSd7ah7nSviK16/itInpmYTEBi/PJ q3964OeR4em/5dSp15ZPmkR1Sx5OzLGPc4DFB0VEH68E86W4IddkvWgTFXu99qc9gPL2DketpkK XSmhf4aCOTJPoew== X-Developer-Key: i=leitao@debian.org; a=openpgp; fpr=AC8539A6E8F46702CA4A439B35A3939FFC78776D X-Debian-User: leitao 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. Sample PG_reserved before the get_hwpoison_page() call. In the MF_COUNT_INCREASED path get_any_page() can drop the caller's reference before returning -EIO, after which the underlying page may have been freed and reallocated with page->flags reset; reading PageReserved(p) at that point would observe stale or unrelated state. The pre-call snapshot reflects what the page actually was at the time of the failure event. Acked-by: Miaohe Lin Reviewed-by: Lance Yang Signed-off-by: Breno Leitao --- mm/memory-failure.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 866c4428ac7ef..f112fb27a8ff6 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -2348,6 +2348,7 @@ int memory_failure(unsigned long pfn, int flags) unsigned long page_flags; bool retry =3D true; int hugetlb =3D 0; + bool is_reserved; =20 if (!sysctl_memory_failure_recovery) panic("Memory failure on page %lx", pfn); @@ -2411,6 +2412,18 @@ int memory_failure(unsigned long pfn, int flags) * In fact it's dangerous to directly bump up page count from 0, * that may make page_ref_freeze()/page_ref_unfreeze() mismatch. */ + /* + * 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. + * + * Sample the flag before get_hwpoison_page(): in the + * MF_COUNT_INCREASED path, get_any_page() can drop the caller's + * reference before returning -EIO, after which page->flags may + * have been reset by the allocator. + */ + is_reserved =3D PageReserved(p); + res =3D get_hwpoison_page(p, flags); if (!res) { if (is_free_buddy_page(p)) { @@ -2432,7 +2445,11 @@ int memory_failure(unsigned long pfn, int flags) } goto unlock_mutex; } else if (res < 0) { - res =3D action_result(pfn, MF_MSG_GET_HWPOISON, MF_IGNORED); + if (is_reserved) + res =3D action_result(pfn, MF_MSG_KERNEL, MF_IGNORED); + else + res =3D action_result(pfn, MF_MSG_GET_HWPOISON, + MF_IGNORED); goto unlock_mutex; } =20 --=20 2.53.0-Meta From nobody Sat Jun 13 02:03:57 2026 Received: from stravinsky.debian.org (stravinsky.debian.org [82.195.75.108]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 09F4140243A; Mon, 11 May 2026 15:39:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=82.195.75.108 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778513974; cv=none; b=l/yp7fVyvt/r1cHd37ZglZlCZD2ESykRERFtD2o0F8XazyvqHhoBj9MQz9O6jFV3z26ut0EkQN1aWhHeFtz75iedY7Ep44S5lvfjui/9DIj+V7A+51kq10ZAwO7RcqGjYlhwjUnyrcVhv8eqqk3TxyVU/5f100LNqr/7N++SPyc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778513974; c=relaxed/simple; bh=Vq/TU+jCW5xnnMwVP7n64LxYlem4v78afndyW+Xnc1E=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=dbrl3ms8EXiyYZ7CjLwJcDDjfUi0Ddfftwcp8/GbJIHYL98pQ+FNDKXYWRqKtjZTLkRNZhJsnBqAhGyyO1CVN/o7pv1B4GG7+USI/Z4/yk+xgWljTwH/ifKAXuMIikRu7jjOrkAxGQXe2kYobcpudpDJH5Dcjfs0BMQyOv7P7NQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=debian.org; spf=pass smtp.mailfrom=debian.org; dkim=pass (2048-bit key) header.d=debian.org header.i=@debian.org header.b=Uop926+6; arc=none smtp.client-ip=82.195.75.108 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=debian.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=debian.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=debian.org header.i=@debian.org header.b="Uop926+6" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=debian.org; s=smtpauto.stravinsky; h=X-Debian-User:Cc:To:In-Reply-To:References: Message-Id:Content-Transfer-Encoding:Content-Type:MIME-Version:Subject:Date: From:Reply-To:Content-ID:Content-Description; bh=xOVy0wpNRxKwqT5M1fLYor5fDbb75VUs7rVqfAvjRcw=; b=Uop926+6t+4cRPk0kGxLjnHIly EW1OIBB+FjdoGl1BBl3D2jxybTKGedam8bMAMZLA61RPOEcUfSXeYBr35H1bBRwZ50K+t400JW0rK RNqMHkXhlijzEBVYQrBKLRQXfOTXNKay2MMjkutxiLs5eH5BXdwM0pfEbQB2uisIu1oUM/1rF8Y2W hpnY/jjUdnAXkX/T6jSPY6W155FpsAwyrhLpy0H7idnKuJUP6u3XpQnkiKfwWCpAvamrdigxlKnCd MlXYOuUOHMoSGYmQBDeB8jdXYdQEHU4gBqMkrd86tM0A6SHwIf4OxKsD3qoyBq9IWP5Re9UtGfHsZ SucZcyrg==; 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 1wMSjD-001hV9-08; Mon, 11 May 2026 15:39:31 +0000 From: Breno Leitao Date: Mon, 11 May 2026 08:38:36 -0700 Subject: [PATCH v6 2/4] mm/memory-failure: classify get_any_page() failures by reason Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260511-ecc_panic-v6-2-183012ba7d4b@debian.org> References: <20260511-ecc_panic-v6-0-183012ba7d4b@debian.org> In-Reply-To: <20260511-ecc_panic-v6-0-183012ba7d4b@debian.org> To: Miaohe Lin , Naoya Horiguchi , Andrew Morton , Jonathan Corbet , Shuah Khan , David Hildenbrand , Lorenzo Stoakes , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Shuah Khan , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , "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, Lance Yang X-Mailer: b4 0.16-dev-d5d98 X-Developer-Signature: v=1; a=openpgp-sha256; l=7619; i=leitao@debian.org; h=from:subject:message-id; bh=Vq/TU+jCW5xnnMwVP7n64LxYlem4v78afndyW+Xnc1E=; b=owEBbQKS/ZANAwAIATWjk5/8eHdtAcsmYgBqAfgg6fw77IZp1166aCin4HRrvDxnTzOvRc/Up zfVMSNRv4qJAjMEAAEIAB0WIQSshTmm6PRnAspKQ5s1o5Of/Hh3bQUCagH4IAAKCRA1o5Of/Hh3 bRIND/9EIWGy+xxLCDjs0WxrQoLiWedbaJ8Om85T1rrASsN4ehnDAgZov3L7CDhah4u3SNhhTNI DY/3c4CCiIQ2PjB2FTGX/OC5kkbabDBBJGzDQ49eBo2yS4AyZs8snxxho4NXjQiJ8JyvC2053Or jm7NtwkCG9c5GSTsoTA7IkOIpZq21grmioJfGL48HxH3ANJw8osZsH73qx4p7wVB7H8guVg3/93 uucAL0Y6ip2nuqGW5IzRTwMt9Fzuuktcx0C7rxfIGhxJoB9H1ap+RMioX373RvFUf+kO5as8rdo r7BuXtpXR/U8HNXDdrxH4Yi9cFJjK5JJWJGWoHKv5lyU/V3htV/xmzr4vjTj/2UDpn7IrfhkSLg q5LQf8cGu9RvszihpH15WNv95DD0ERa3jw1HgnjgtvvYtsbRPhXFQpBOTlU8nwathyVCvGIyAOo oG2CTnrodz2V8/dW1+hQU7b/g8VyFKwnbb6uXKWXL7RBEwi2onIkjalpc4GrxGoOfeuNaMTNJkw KbESAvDCyMBtYjdkn5Na+84be6rxYSWGAaYA0NBJDr/jtVBX6Br9hehHoBfOAhDxnFlY8UWsoHT CtfWTOrVDrLTsOToTTzOElyXc9lTy8jJ+E3OJ+C/WH3h3UJNRPF3RGboIr7gHM7mUtNsIL+6eEG zZLBlW9DQ+gtYZw== X-Developer-Key: i=leitao@debian.org; a=openpgp; fpr=AC8539A6E8F46702CA4A439B35A3939FFC78776D X-Debian-User: leitao When get_any_page() fails to grab a page reference, the *reason* it failed is known at the call site but is not surfaced to callers: the HWPoisonHandlable() rejection path (a stable kernel page hwpoison cannot handle =E2=80=94 slab, vmalloc, page tables, kernel stacks, ...) and the page_count() / put_page race paths (a transient page-allocator lifecycle race) all collapse to a single negative errno by the time memory_failure() sees them. memory_failure() can only observe the conflated result and reports both as MF_MSG_GET_HWPOISON. Surface the diagnosis explicitly. Add an mf_get_page_status enum, plumbed out through get_any_page() and get_hwpoison_page() (NULL is accepted by callers that do not care =E2=80=94 unpoison_memory() and soft_offline_page() pass NULL). get_any_page() sets the status at the moment it gives up: MF_GET_PAGE_UNHANDLABLE =E2=80=94 HWPoisonHandlable() rejected the page after retries. MF_GET_PAGE_RACE =E2=80=94 exhausted retries on a refcount / lifecycle race with the allocator. memory_failure() then promotes the unhandlable case to MF_MSG_KERNEL alongside the existing PageReserved branch, and leaves the transient-race case as MF_MSG_GET_HWPOISON. This forms the foundation a later patch will rely on to decide whether an unrecoverable failure should panic. Drop the "reserved" qualifier from action_page_types[MF_MSG_KERNEL] and the matching tracepoint string in MF_PAGE_TYPE: the enum value now covers both PageReserved pages and unhandlable kernel pages (slab, vmalloc, page tables, kernel stacks, ...), so "kernel page" is the accurate label for both populations. Suggested-by: Lance Yang Signed-off-by: Breno Leitao --- include/trace/events/memory-failure.h | 2 +- mm/memory-failure.c | 46 +++++++++++++++++++++++++++++--= ---- 2 files changed, 39 insertions(+), 9 deletions(-) diff --git a/include/trace/events/memory-failure.h b/include/trace/events/m= emory-failure.h index aa57cc8f896be..8a860e6fcb4e9 100644 --- a/include/trace/events/memory-failure.h +++ b/include/trace/events/memory-failure.h @@ -24,7 +24,7 @@ EMe ( MF_RECOVERED, "Recovered" ) =20 #define MF_PAGE_TYPE \ - EM ( MF_MSG_KERNEL, "reserved kernel page" ) \ + EM ( MF_MSG_KERNEL, "kernel page" ) \ EM ( MF_MSG_KERNEL_HIGH_ORDER, "high-order kernel page" ) \ EM ( MF_MSG_HUGE, "huge page" ) \ EM ( MF_MSG_FREE_HUGE, "free huge page" ) \ diff --git a/mm/memory-failure.c b/mm/memory-failure.c index f112fb27a8ff6..4210173060aac 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -878,7 +878,7 @@ static const char *action_name[] =3D { }; =20 static const char * const action_page_types[] =3D { - [MF_MSG_KERNEL] =3D "reserved kernel page", + [MF_MSG_KERNEL] =3D "kernel page", [MF_MSG_KERNEL_HIGH_ORDER] =3D "high-order kernel page", [MF_MSG_HUGE] =3D "huge page", [MF_MSG_FREE_HUGE] =3D "free huge page", @@ -1389,11 +1389,29 @@ static int __get_hwpoison_page(struct page *page, u= nsigned long flags) =20 #define GET_PAGE_MAX_RETRY_NUM 3 =20 -static int get_any_page(struct page *p, unsigned long flags) +enum mf_get_page_status { + MF_GET_PAGE_OK =3D 0, + MF_GET_PAGE_RACE, + MF_GET_PAGE_UNHANDLABLE, +}; + +static void set_mf_get_page_status(enum mf_get_page_status *gp_status, + enum mf_get_page_status value) +{ + if (!gp_status) + return; + + *gp_status =3D value; +} + +static int get_any_page(struct page *p, unsigned long flags, + enum mf_get_page_status *gp_status) { int ret =3D 0, pass =3D 0; bool count_increased =3D false; =20 + set_mf_get_page_status(gp_status, MF_GET_PAGE_OK); + if (flags & MF_COUNT_INCREASED) count_increased =3D true; =20 @@ -1406,11 +1424,13 @@ static int get_any_page(struct page *p, unsigned lo= ng flags) if (pass++ < GET_PAGE_MAX_RETRY_NUM) goto try_again; ret =3D -EBUSY; + set_mf_get_page_status(gp_status, MF_GET_PAGE_RACE); } else if (!PageHuge(p) && !is_free_buddy_page(p)) { /* We raced with put_page, retry. */ if (pass++ < GET_PAGE_MAX_RETRY_NUM) goto try_again; ret =3D -EIO; + set_mf_get_page_status(gp_status, MF_GET_PAGE_RACE); } goto out; } else if (ret =3D=3D -EBUSY) { @@ -1423,6 +1443,7 @@ static int get_any_page(struct page *p, unsigned long= flags) goto try_again; } ret =3D -EIO; + set_mf_get_page_status(gp_status, MF_GET_PAGE_UNHANDLABLE); goto out; } } @@ -1442,6 +1463,7 @@ static int get_any_page(struct page *p, unsigned long= flags) } put_page(p); ret =3D -EIO; + set_mf_get_page_status(gp_status, MF_GET_PAGE_UNHANDLABLE); } out: if (ret =3D=3D -EIO) @@ -1480,6 +1502,7 @@ static int __get_unpoison_page(struct page *page) * get_hwpoison_page() - Get refcount for memory error handling * @p: Raw error page (hit by memory error) * @flags: Flags controlling behavior of error handling + * @gp_status: Optional output for the reason get_any_page() failed * * get_hwpoison_page() takes a page refcount of an error page to handle me= mory * error on it, after checking that the error page is in a well-defined st= ate @@ -1503,7 +1526,8 @@ static int __get_unpoison_page(struct page *page) * operations like allocation and free, * -EHWPOISON when the page is hwpoisoned and taken off from buddy. */ -static int get_hwpoison_page(struct page *p, unsigned long flags) +static int get_hwpoison_page(struct page *p, unsigned long flags, + enum mf_get_page_status *gp_status) { int ret; =20 @@ -1511,7 +1535,7 @@ static int get_hwpoison_page(struct page *p, unsigned= long flags) if (flags & MF_UNPOISON) ret =3D __get_unpoison_page(p); else - ret =3D get_any_page(p, flags); + ret =3D get_any_page(p, flags, gp_status); zone_pcp_enable(page_zone(p)); =20 return ret; @@ -2349,6 +2373,7 @@ int memory_failure(unsigned long pfn, int flags) bool retry =3D true; int hugetlb =3D 0; bool is_reserved; + enum mf_get_page_status gp_status =3D MF_GET_PAGE_OK; =20 if (!sysctl_memory_failure_recovery) panic("Memory failure on page %lx", pfn); @@ -2424,7 +2449,7 @@ int memory_failure(unsigned long pfn, int flags) */ is_reserved =3D PageReserved(p); =20 - res =3D get_hwpoison_page(p, flags); + res =3D get_hwpoison_page(p, flags, &gp_status); if (!res) { if (is_free_buddy_page(p)) { if (take_page_off_buddy(p)) { @@ -2445,7 +2470,12 @@ int memory_failure(unsigned long pfn, int flags) } goto unlock_mutex; } else if (res < 0) { - if (is_reserved) + /* + * Promote a stable unhandlable kernel page diagnosed by + * get_hwpoison_page() to MF_MSG_KERNEL alongside reserved + * pages; transient lifecycle races stay as MF_MSG_GET_HWPOISON. + */ + if (is_reserved || gp_status =3D=3D MF_GET_PAGE_UNHANDLABLE) res =3D action_result(pfn, MF_MSG_KERNEL, MF_IGNORED); else res =3D action_result(pfn, MF_MSG_GET_HWPOISON, @@ -2750,7 +2780,7 @@ int unpoison_memory(unsigned long pfn) goto unlock_mutex; } =20 - ghp =3D get_hwpoison_page(p, MF_UNPOISON); + ghp =3D get_hwpoison_page(p, MF_UNPOISON, NULL); if (!ghp) { if (folio_test_hugetlb(folio)) { huge =3D true; @@ -2957,7 +2987,7 @@ int soft_offline_page(unsigned long pfn, int flags) =20 retry: get_online_mems(); - ret =3D get_hwpoison_page(page, flags | MF_SOFT_OFFLINE); + ret =3D get_hwpoison_page(page, flags | MF_SOFT_OFFLINE, NULL); put_online_mems(); =20 if (hwpoison_filter(page)) { --=20 2.53.0-Meta From nobody Sat Jun 13 02:03:57 2026 Received: from stravinsky.debian.org (stravinsky.debian.org [82.195.75.108]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5753432E137; Mon, 11 May 2026 15:39:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=82.195.75.108 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778513982; cv=none; b=iLT3PKObx5UZnjjs2YvOgQrxwAkaAcsrp3c8sChTIWXl4v59ZTnUHXDV7JpHhNyI0Xp28fNomKJwoYZGE9fpsJ1TnZ4qZVGrfihvO+La0gflaLb/bMTWZFJT4t74m4js5HR3MHc1L/zrBbnSKXEesdDYps28cedAsnIS90g1J0g= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778513982; c=relaxed/simple; bh=3WH08KBPaFAFZH+gyAtBCRzaUv1S7Oemd/2clegvfv0=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=ISpXcYn9BN9KXQwqpYoP4S/P79nGmhfwZNt35qipHs7S+aVgDEzEYT4tzzqh6LMbQdHhhgiKi4y7W+FRXTIPUKvCP57v6vs+wpEhekZ/xjRElaz0prGp+up9NSV55mwhCpxbpMesS5YNmiRupFUCrMLU3tKgKkvUN82O2ogk6cg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=debian.org; spf=pass smtp.mailfrom=debian.org; dkim=pass (2048-bit key) header.d=debian.org header.i=@debian.org header.b=SoEFslgk; arc=none smtp.client-ip=82.195.75.108 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=debian.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=debian.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=debian.org header.i=@debian.org header.b="SoEFslgk" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=debian.org; s=smtpauto.stravinsky; h=X-Debian-User:Cc:To:In-Reply-To:References: Message-Id:Content-Transfer-Encoding:Content-Type:MIME-Version:Subject:Date: From:Reply-To:Content-ID:Content-Description; bh=9eczhBxewuo2JvFN1og+M00zMC+sIzResfPi7F2/71E=; b=SoEFslgknWcDSrruLzc6WlAxLC 3mMn9cFGHBHyFJi/up4p4QPSrz3kdxwOGdJElMDREJSORbSiZvg2hY5Dn9IezBsFyhvvDLguunyCr VBsxzu+Ulhl9ZsJAaNe3Nh6e+tFYQnigtazd4YO47qvyw34mUo+Ra2325C++qZv6it22oqvmOOZdY s6fwrg6MNbvjKU9p0hMWET1VvNtipiqpPGuphB5Kc6+DU7S5f9jrqt3IofvnC8x3LJ45Ei+RYOL29 zFO1DCWRfd9iA74ZzmPT1cWZeOGqRfxzIMPWzOuGYzI+PG51bnsffpGwQKA/R71IHqzar9N0nCCcP kBvHKLyA==; 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 1wMSjI-001hVR-2i; Mon, 11 May 2026 15:39:37 +0000 From: Breno Leitao Date: Mon, 11 May 2026 08:38:37 -0700 Subject: [PATCH v6 3/4] mm/memory-failure: add panic option for unrecoverable pages Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260511-ecc_panic-v6-3-183012ba7d4b@debian.org> References: <20260511-ecc_panic-v6-0-183012ba7d4b@debian.org> In-Reply-To: <20260511-ecc_panic-v6-0-183012ba7d4b@debian.org> To: Miaohe Lin , Naoya Horiguchi , Andrew Morton , Jonathan Corbet , Shuah Khan , David Hildenbrand , Lorenzo Stoakes , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Shuah Khan , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , "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=3232; i=leitao@debian.org; h=from:subject:message-id; bh=3WH08KBPaFAFZH+gyAtBCRzaUv1S7Oemd/2clegvfv0=; b=owEBbQKS/ZANAwAIATWjk5/8eHdtAcsmYgBqAfgg6LbRP3E9quuqNfU29bb3SDfqIGPF51mon h5IfI1EdvCJAjMEAAEIAB0WIQSshTmm6PRnAspKQ5s1o5Of/Hh3bQUCagH4IAAKCRA1o5Of/Hh3 bWJMD/9DaFTTwirbNnP+mpFf7x8UBJ81HYXeu/QS51MfqGkVR5U0eG8Gt8zRRtiJ0/PAHebDQmG zgKlONyzGuBhm7oq3WF4pQNUZ5qVKFpkGwvuEA+oGbQKbcGDsxM6FkUAljo3DlLcpjGKthEBzmP CZlULeNx4WzgL84wQGxPV2GWJCuBIUkZj9UV6nmy5aHDzY+xXewm3thrlxq4ihM2mB9pIDfz+LP 6bZnLR4hkkK4un09+UfW7dpzbfJb4Jdpsh8W+qJBh3cMUf3Y0dmyyJ+RoB+2ang38KizQCQgqC1 2hiCemU76StagplXoRk00IJy9bv/pXiW4y8xKC2KMOFgv7cUysb3TWRDhGA0VRAN68ygySBUI6t JNjIdKEcGTcSdZOFlvbYgys/UmvGLIY/pEPqN+WsMOr2Uk1BiJGTSgxvgLGwMFCbhSoXLJaYpYj ZICAIAms0EohYnzuWMdlZlveLfSyTdVqhIzK1z9K8J6U5w4IYwiwOWUgAWvfrqPJxeE9AgH6MKi 7Bvq4oNRKhMIDoogOtNvi5fKX3PD1gaFsRX0qBM0iKt6wQX4c8IyE75wTnkgsVzjptLO7MuV331 ZQnnr2ONPSZ+u5Kpw7NA9rBp29QxCWT+TpSmmlS6dwKg5aCGTHIhw2mRISNo7thyCu+4/9jHqf/ a1k53Ji8sW2fbNA== X-Developer-Key: i=leitao@debian.org; a=openpgp; fpr=AC8539A6E8F46702CA4A439B35A3939FFC78776D X-Debian-User: leitao Add a sysctl panic_on_unrecoverable_memory_failure that triggers a kernel panic when memory_failure() encounters pages that cannot be recovered. This provides a clean crash with useful debug information rather than allowing silent data corruption or a delayed crash at an unrelated code path. Panic eligibility is intentionally narrow: only MF_MSG_KERNEL with result =3D=3D MF_IGNORED panics. That covers reserved pages (PageReserved) and the kernel page types that the prior patch promotes from MF_MSG_GET_HWPOISON via MF_GET_PAGE_UNHANDLABLE =E2=80=94 slab, vmalloc, pa= ge tables, kernel stacks, and similar non-LRU/non-buddy kernel-owned pages. All other action types are excluded: - MF_MSG_GET_HWPOISON and MF_MSG_KERNEL_HIGH_ORDER can be reached by transient refcount races with the page allocator (an in-flight buddy allocation has refcount 0 and is no longer on the buddy free list, briefly), and panicking on them would risk killing the box for what is actually a recoverable userspace page. - MF_MSG_UNKNOWN means identify_page_state() could not classify the page; that is precisely the wrong basis for a panic decision. Signed-off-by: Breno Leitao --- mm/memory-failure.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 4210173060aac..e4a9ceacaf36b 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -74,6 +74,8 @@ static int sysctl_memory_failure_recovery __read_mostly = =3D 1; =20 static int sysctl_enable_soft_offline __read_mostly =3D 1; =20 +static int sysctl_panic_on_unrecoverable_mf __read_mostly; + atomic_long_t num_poisoned_pages __read_mostly =3D ATOMIC_LONG_INIT(0); =20 static bool hw_memory_failure __read_mostly =3D false; @@ -155,6 +157,15 @@ static const struct ctl_table memory_failure_table[] = =3D { .proc_handler =3D proc_dointvec_minmax, .extra1 =3D SYSCTL_ZERO, .extra2 =3D SYSCTL_ONE, + }, + { + .procname =3D "panic_on_unrecoverable_memory_failure", + .data =3D &sysctl_panic_on_unrecoverable_mf, + .maxlen =3D sizeof(sysctl_panic_on_unrecoverable_mf), + .mode =3D 0644, + .proc_handler =3D proc_dointvec_minmax, + .extra1 =3D SYSCTL_ZERO, + .extra2 =3D SYSCTL_ONE, } }; =20 @@ -1281,6 +1292,18 @@ static void update_per_node_mf_stats(unsigned long p= fn, ++mf_stats->total; } =20 +static bool panic_on_unrecoverable_mf(enum mf_action_page_type type, + enum mf_result result) +{ + if (!sysctl_panic_on_unrecoverable_mf || result !=3D MF_IGNORED) + return false; + + if (type =3D=3D MF_MSG_KERNEL) + return true; + + return false; +} + /* * "Dirty/Clean" indication is not 100% accurate due to the possibility of * setting PG_dirty outside page lock. See also comment above set_page_dir= ty(). @@ -1298,6 +1321,9 @@ static int action_result(unsigned long pfn, enum mf_a= ction_page_type type, pr_err("%#lx: recovery action for %s: %s\n", pfn, action_page_types[type], action_name[result]); =20 + if (panic_on_unrecoverable_mf(type, result)) + panic("Memory failure: %#lx: unrecoverable page", pfn); + return (result =3D=3D MF_RECOVERED || result =3D=3D MF_DELAYED) ? 0 : -EB= USY; } =20 --=20 2.53.0-Meta From nobody Sat Jun 13 02:03:57 2026 Received: from stravinsky.debian.org (stravinsky.debian.org [82.195.75.108]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2F54140242A; Mon, 11 May 2026 15:39:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=82.195.75.108 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778513988; cv=none; b=XMjPwIXU9xRxZdOrUPjl+i4pbWNU1wp+TzaNKakcNDg1myr6Nqa6LIOp8a6xy0GD79ryi4VKrov34ezeYZaqu2PpqncamKYnxrUQlFkOdq/IJC2eUOVxr2bEjV85iiT0Kb3U3Kz8xlzX0qGKQ2otzD8A2CHh0Qz1pBqXRdJfqBY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778513988; c=relaxed/simple; bh=Q+ABac2nobHr/s0/5BCHnN9Y3bSYo92z/wSIvYBKopg=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=DNtgp8mGtuQKKWg0MdInh5yTTFM3Ui8d8DHrmWdNbk9TO7XnAyYX3tGGKNcbEjslr51cTLn7QGRQBIuyLU/r76YAhCbC3+l9lBK46bCa3bOM/9PQELdKHrx9Je4KZRCDAJIIUmaUc0MIK58o1nd/VzVTGd04hPQi/7Hfsu6E84o= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=debian.org; spf=pass smtp.mailfrom=debian.org; dkim=pass (2048-bit key) header.d=debian.org header.i=@debian.org header.b=wHpPbeXo; arc=none smtp.client-ip=82.195.75.108 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=debian.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=debian.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=debian.org header.i=@debian.org header.b="wHpPbeXo" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=debian.org; s=smtpauto.stravinsky; h=X-Debian-User:Cc:To:In-Reply-To:References: Message-Id:Content-Transfer-Encoding:Content-Type:MIME-Version:Subject:Date: From:Reply-To:Content-ID:Content-Description; bh=C+tCS04YBf4yWLUQhQUZajCDPpB2s5wPhqtGUXXQBCg=; b=wHpPbeXoMK5MT1JH7k3UWAIHXT YPhq7Iw77BUECX985/6TGJ3de5iiLXQETl29UH4yo9QyzbhHFF3vL75PGK2h5+vNAzZa8dmfx9fro /F75vzIx3aP1KX/3AoJJ0mDB8HdZ/Bv5fyu82u6M7NxvBIGURg3ucKJiwiwtMa1j9NWU+9fFvAjEo jSi+muMc+aodWrzb84/a4beXBV+F0vGCL6p2NR/0Hp8S497GKSJdAwz3moLL2hR+JsFb17zgKLw0V QKhyOUzgJ6F0BBNA6KTPNdSbyr8ULW9j59BLU5MxdLmn8Yq5RcqCCfMXCqr5eYdgLY9EmoMDsPDw6 mThJA90Q==; 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 1wMSjO-001hVi-1k; Mon, 11 May 2026 15:39:42 +0000 From: Breno Leitao Date: Mon, 11 May 2026 08:38:38 -0700 Subject: [PATCH v6 4/4] Documentation: document panic_on_unrecoverable_memory_failure sysctl Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260511-ecc_panic-v6-4-183012ba7d4b@debian.org> References: <20260511-ecc_panic-v6-0-183012ba7d4b@debian.org> In-Reply-To: <20260511-ecc_panic-v6-0-183012ba7d4b@debian.org> To: Miaohe Lin , Naoya Horiguchi , Andrew Morton , Jonathan Corbet , Shuah Khan , David Hildenbrand , Lorenzo Stoakes , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Shuah Khan , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , "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=4250; i=leitao@debian.org; h=from:subject:message-id; bh=Q+ABac2nobHr/s0/5BCHnN9Y3bSYo92z/wSIvYBKopg=; b=owEBbQKS/ZANAwAIATWjk5/8eHdtAcsmYgBqAfggExFOzTNiSrshYAhWzivg+fyoMl0UHn1Ol k/baPddoo2JAjMEAAEIAB0WIQSshTmm6PRnAspKQ5s1o5Of/Hh3bQUCagH4IAAKCRA1o5Of/Hh3 bSYoD/9wpkfhqpU3NW837qbyKkH5PtTXq/mLXGB9M/kyPbi/lbjrhtclHCid5vxa0hjuNNXSWM+ rjYPOBkE5+yr3G3fvTQ6x0ilNHObfL/mIlrbudRUeyD/AdWO5Py0u3BGlXS7EmgKsUNhNRCydwq LLUKeo9F6zk1uaTsdttH0fH0whh1OUIfSYawJwMN3yhybIyoiiPyZM8LpodWjJPgIKE8X37wKMK CU0IrV9EqhOo+5Xpdp+TSi1YNJm4WPqt25g1p6GcP8Bv9+JNsKl9nFzfJxJ67nY3Yb8580z5kQy FjbsK7ev9NciRGRpptWMCCe3Jct0m8nm6gqTJvNXpHMrh5UfX7woZ3NpkmP4+dIZvVFWGQe7sqo RiFoPB7UxxevtzgkBglm6ac8kqQ6dAqfbPWAxSmwJ7U/B72jONwFccgvj/DgSXWWNNES3Avc8IL FBGIWQmkD4Yht6YtpDvz5pTgVibcRT0mopLbGxZel8PGK+8ROneMoK0pv+94JcDcYCZkOHj7RHy 477VvpdIPxBxaj3ew8chVn1yvFb0wApmgnpR2vwwungePtd8UTo5o8jFebr7PrDUGGyiTvcytUz TMUHDk09qF+spb7VnVYTx/nEkoOi7NucFih/niGo88XheO1J6daCVgLpFrSBdydI88Y8HJBgw4Y d+Rhi92mvN4p4Jw== X-Developer-Key: i=leitao@debian.org; a=openpgp; fpr=AC8539A6E8F46702CA4A439B35A3939FFC78776D X-Debian-User: leitao Add documentation for the new vm.panic_on_unrecoverable_memory_failure sysctl, describing which failures trigger a panic (kernel-owned pages the handler cannot recover) and which are intentionally left out (transient allocator races and unclassified pages). Signed-off-by: Breno Leitao --- Documentation/admin-guide/sysctl/vm.rst | 70 +++++++++++++++++++++++++++++= ++++ 1 file changed, 70 insertions(+) diff --git a/Documentation/admin-guide/sysctl/vm.rst b/Documentation/admin-= guide/sysctl/vm.rst index 97e12359775c9..802c51ba8c43b 100644 --- a/Documentation/admin-guide/sysctl/vm.rst +++ b/Documentation/admin-guide/sysctl/vm.rst @@ -67,6 +67,7 @@ Currently, these files are in /proc/sys/vm: - page-cluster - page_lock_unfairness - panic_on_oom +- panic_on_unrecoverable_memory_failure - percpu_pagelist_high_fraction - stat_interval - stat_refresh @@ -925,6 +926,75 @@ panic_on_oom=3D2+kdump gives you very strong tool to i= nvestigate why oom happens. You can get snapshot. =20 =20 +panic_on_unrecoverable_memory_failure +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D + +When a hardware memory error (e.g. multi-bit ECC) hits a kernel page +that cannot be recovered by the memory failure handler, the default +behaviour is to ignore the error and continue operation. This is +dangerous because the corrupted data remains accessible to the kernel, +risking silent data corruption or a delayed crash when the poisoned +memory is next accessed. + +When enabled, this sysctl triggers a panic on kernel-owned pages that +the memory failure handler cannot recover: reserved pages +(``PageReserved``) and stable kernel pages that hwpoison cannot handle +(slab, vmalloc, page tables, kernel stacks, and similar non-LRU, +non-buddy pages). + +Other failure paths are intentionally left out because they can be +reached by transient races with the page allocator (an in-flight +buddy allocation has refcount 0 and is no longer on the buddy free +list, briefly), and panicking on them would risk killing the box for +a page that was actually destined for userspace where the standard +SIGBUS recovery path applies. Pages whose state could not be +classified at all are also not covered, since an unknown state is +not a sound basis for a panic decision. + +For many environments it is preferable to panic immediately with a clean +crash dump that captures the original error context, rather than to +continue and face a random crash later whose cause is difficult to +diagnose. + +Use cases +--------- + +This option is most useful in environments where unattributed crashes +are expensive to debug or where data integrity must take precedence +over availability: + +* Large fleets, where multi-bit ECC errors on kernel pages are observed + regularly and post-mortem analysis of an unrelated downstream crash + (often seconds to minutes after the original error) consumes + significant engineering effort. + +* Systems configured with kdump, where panicking at the moment of the + hardware error produces a vmcore that still contains the faulting + address, the affected page state, and the originating MCE/GHES + record =E2=80=94 context that is typically lost by the time a delayed cr= ash + occurs. + +* High-availability clusters that rely on fast, deterministic node + failure for failover, and prefer an immediate panic over silent data + corruption propagating to replicas or persistent storage. + +* Kernel and platform developers reproducing hwpoison issues with + tools such as ``mce-inject`` or error-injection debugfs interfaces, + where panicking on the unrecoverable path makes regressions + immediately visible instead of surfacing as later, unrelated + failures. + +=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D +0 Try to continue operation (default). +1 Panic immediately. If the ``panic`` sysctl is also non-zero then the + machine will be rebooted. +=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D + +Example:: + + echo 1 > /proc/sys/vm/panic_on_unrecoverable_memory_failure + + percpu_pagelist_high_fraction =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D =20 --=20 2.53.0-Meta