From: Michal Hocko <mhocko@kernel.org> To: Mikhail Zaslonko <zaslonko@linux.ibm.com>, Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org>, Pavel Tatashin <pasha.tatashin@soleen.com>, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, gerald.schaefer@de.ibm.com, linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>, Michal Hocko <mhocko@suse.com> Subject: [PATCH 2/2] mm, memory_hotplug: test_pages_in_a_zone do not pass the end of zone Date: Mon, 28 Jan 2019 15:45:06 +0100 [thread overview] Message-ID: <20190128144506.15603-3-mhocko@kernel.org> (raw) In-Reply-To: <20190128144506.15603-1-mhocko@kernel.org> From: Mikhail Zaslonko <zaslonko@linux.ibm.com> If memory end is not aligned with the sparse memory section boundary, the mapping of such a section is only partly initialized. This may lead to VM_BUG_ON due to uninitialized struct pages access from test_pages_in_a_zone() function triggered by memory_hotplug sysfs handlers. Here are the the panic examples: CONFIG_DEBUG_VM_PGFLAGS=y kernel parameter mem=2050M -------------------------- page:000003d082008000 is uninitialized and poisoned page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p)) Call Trace: ([<0000000000385b26>] test_pages_in_a_zone+0xde/0x160) [<00000000008f15c4>] show_valid_zones+0x5c/0x190 [<00000000008cf9c4>] dev_attr_show+0x34/0x70 [<0000000000463ad0>] sysfs_kf_seq_show+0xc8/0x148 [<00000000003e4194>] seq_read+0x204/0x480 [<00000000003b53ea>] __vfs_read+0x32/0x178 [<00000000003b55b2>] vfs_read+0x82/0x138 [<00000000003b5be2>] ksys_read+0x5a/0xb0 [<0000000000b86ba0>] system_call+0xdc/0x2d8 Last Breaking-Event-Address: [<0000000000385b26>] test_pages_in_a_zone+0xde/0x160 Kernel panic - not syncing: Fatal exception: panic_on_oops Fix this by checking whether the pfn to check is within the zone. [mhocko@suse.com: separated this change from http://lkml.kernel.org/r/20181105150401.97287-2-zaslonko@linux.ibm.com] Signed-off-by: Mikhail Zaslonko <zaslonko@linux.ibm.com> Signed-off-by: Michal Hocko <mhocko@suse.com> --- mm/memory_hotplug.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 07872789d778..7711d0e327b6 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1274,6 +1274,9 @@ int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn, i++; if (i == MAX_ORDER_NR_PAGES || pfn + i >= end_pfn) continue; + /* Check if we got outside of the zone */ + if (zone && !zone_spans_pfn(zone, pfn + i)) + return 0; page = pfn_to_page(pfn + i); if (zone && page_zone(page) != zone) return 0; -- 2.20.1
WARNING: multiple messages have this Message-ID (diff)
From: Michal Hocko <mhocko@kernel.org> To: Mikhail Zaslonko <zaslonko@linux.ibm.com>, Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org>, Pavel Tatashin <pasha.tatashin@soleen.com>, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, gerald.schaefer@de.ibm.com, <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org>, Michal Hocko <mhocko@suse.com> Subject: [PATCH 2/2] mm, memory_hotplug: test_pages_in_a_zone do not pass the end of zone Date: Mon, 28 Jan 2019 15:45:06 +0100 [thread overview] Message-ID: <20190128144506.15603-3-mhocko@kernel.org> (raw) Message-ID: <20190128144506.g_vYVQlYx-cqIrKnrWBdNVwTZMsURcuBdLsVYhxFgsg@z> (raw) In-Reply-To: <20190128144506.15603-1-mhocko@kernel.org> From: Mikhail Zaslonko <zaslonko@linux.ibm.com> If memory end is not aligned with the sparse memory section boundary, the mapping of such a section is only partly initialized. This may lead to VM_BUG_ON due to uninitialized struct pages access from test_pages_in_a_zone() function triggered by memory_hotplug sysfs handlers. Here are the the panic examples: CONFIG_DEBUG_VM_PGFLAGS=y kernel parameter mem=2050M -------------------------- page:000003d082008000 is uninitialized and poisoned page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p)) Call Trace: ([<0000000000385b26>] test_pages_in_a_zone+0xde/0x160) [<00000000008f15c4>] show_valid_zones+0x5c/0x190 [<00000000008cf9c4>] dev_attr_show+0x34/0x70 [<0000000000463ad0>] sysfs_kf_seq_show+0xc8/0x148 [<00000000003e4194>] seq_read+0x204/0x480 [<00000000003b53ea>] __vfs_read+0x32/0x178 [<00000000003b55b2>] vfs_read+0x82/0x138 [<00000000003b5be2>] ksys_read+0x5a/0xb0 [<0000000000b86ba0>] system_call+0xdc/0x2d8 Last Breaking-Event-Address: [<0000000000385b26>] test_pages_in_a_zone+0xde/0x160 Kernel panic - not syncing: Fatal exception: panic_on_oops Fix this by checking whether the pfn to check is within the zone. [mhocko@suse.com: separated this change from http://lkml.kernel.org/r/20181105150401.97287-2-zaslonko@linux.ibm.com] Signed-off-by: Mikhail Zaslonko <zaslonko@linux.ibm.com> Signed-off-by: Michal Hocko <mhocko@suse.com> --- mm/memory_hotplug.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 07872789d778..7711d0e327b6 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1274,6 +1274,9 @@ int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn, i++; if (i == MAX_ORDER_NR_PAGES || pfn + i >= end_pfn) continue; + /* Check if we got outside of the zone */ + if (zone && !zone_spans_pfn(zone, pfn + i)) + return 0; page = pfn_to_page(pfn + i); if (zone && page_zone(page) != zone) return 0; -- 2.20.1
next prev parent reply other threads:[~2019-01-28 14:45 UTC|newest] Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-01-28 14:45 [PATCH 0/2] mm, memory_hotplug: fix uninitialized pages fallouts Michal Hocko 2019-01-28 14:45 ` Michal Hocko 2019-01-28 14:45 ` [PATCH 1/2] mm, memory_hotplug: is_mem_section_removable do not pass the end of a zone Michal Hocko 2019-01-28 14:45 ` Michal Hocko 2019-01-29 9:06 ` Oscar Salvador 2019-01-29 9:12 ` Michal Hocko 2019-01-30 7:54 ` Oscar Salvador 2019-01-28 14:45 ` Michal Hocko [this message] 2019-01-28 14:45 ` [PATCH 2/2] mm, memory_hotplug: test_pages_in_a_zone do not pass the end of zone Michal Hocko 2019-01-29 9:09 ` Oscar Salvador 2019-01-29 9:13 ` Michal Hocko 2019-01-28 17:50 ` [PATCH 0/2] mm, memory_hotplug: fix uninitialized pages fallouts Andrew Morton 2019-01-28 17:50 ` Andrew Morton 2019-01-28 18:41 ` Michal Hocko 2019-01-28 18:45 ` Michal Hocko 2019-01-29 13:14 ` Gerald Schaefer 2019-01-29 13:49 ` Michal Hocko 2019-01-29 14:08 ` Gerald Schaefer 2019-01-29 17:38 ` Mikhail Gavrilov 2019-01-29 20:24 ` Michal Hocko 2019-01-29 20:56 ` Mikhail Gavrilov
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