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 1/2] mm, memory_hotplug: is_mem_section_removable do not pass the end of a zone Date: Mon, 28 Jan 2019 15:45:05 +0100 [thread overview] Message-ID: <20190128144506.15603-2-mhocko@kernel.org> (raw) In-Reply-To: <20190128144506.15603-1-mhocko@kernel.org> From: Michal Hocko <mhocko@suse.com> Mikhail has reported the following VM_BUG_ON triggered when reading sysfs removable state of a memory block: 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 The reason is that the memory block spans the zone boundary and we are stumbling over an unitialized struct page. Fix this by enforcing zone range in is_mem_section_removable so that we never run away from a zone. Reported-by: Mikhail Zaslonko <zaslonko@linux.ibm.com> Debugged-by: Mikhail Zaslonko <zaslonko@linux.ibm.com> Signed-off-by: Michal Hocko <mhocko@suse.com> --- mm/memory_hotplug.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index b9a667d36c55..07872789d778 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1233,7 +1233,8 @@ static bool is_pageblock_removable_nolock(struct page *page) bool is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages) { struct page *page = pfn_to_page(start_pfn); - struct page *end_page = page + nr_pages; + unsigned long end_pfn = min(start_pfn + nr_pages, zone_end_pfn(page_zone(page))); + struct page *end_page = pfn_to_page(end_pfn); /* Check the starting page of each pageblock within the range */ for (; page < end_page; page = next_active_pageblock(page)) { -- 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 1/2] mm, memory_hotplug: is_mem_section_removable do not pass the end of a zone Date: Mon, 28 Jan 2019 15:45:05 +0100 [thread overview] Message-ID: <20190128144506.15603-2-mhocko@kernel.org> (raw) Message-ID: <20190128144505.2G7S1gir_0P1_M3LDhMLV_OwMGsDRN_OiuJsaPyyJNg@z> (raw) In-Reply-To: <20190128144506.15603-1-mhocko@kernel.org> From: Michal Hocko <mhocko@suse.com> Mikhail has reported the following VM_BUG_ON triggered when reading sysfs removable state of a memory block: 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 The reason is that the memory block spans the zone boundary and we are stumbling over an unitialized struct page. Fix this by enforcing zone range in is_mem_section_removable so that we never run away from a zone. Reported-by: Mikhail Zaslonko <zaslonko@linux.ibm.com> Debugged-by: Mikhail Zaslonko <zaslonko@linux.ibm.com> Signed-off-by: Michal Hocko <mhocko@suse.com> --- mm/memory_hotplug.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index b9a667d36c55..07872789d778 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1233,7 +1233,8 @@ static bool is_pageblock_removable_nolock(struct page *page) bool is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages) { struct page *page = pfn_to_page(start_pfn); - struct page *end_page = page + nr_pages; + unsigned long end_pfn = min(start_pfn + nr_pages, zone_end_pfn(page_zone(page))); + struct page *end_page = pfn_to_page(end_pfn); /* Check the starting page of each pageblock within the range */ for (; page < end_page; page = next_active_pageblock(page)) { -- 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 ` Michal Hocko [this message] 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 2019-01-29 9:06 ` Oscar Salvador 2019-01-29 9:12 ` Michal Hocko 2019-01-30 7:54 ` Oscar Salvador 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 2019-01-28 14:45 ` 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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