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Anshuman Khandual 1636b5e9c3 mm/ptdump: take the memory hotplug lock inside ptdump_walk_pgd() commit `59305202c6` upstream. Memory hot remove unmaps and tears down various kernel page table regions as required. The ptdump code can race with concurrent modifications of the kernel page tables. When leaf entries are modified concurrently, the dump code may log stale or inconsistent information for a VA range, but this is otherwise not harmful. But when intermediate levels of kernel page table are freed, the dump code will continue to use memory that has been freed and potentially reallocated for another purpose. In such cases, the ptdump code may dereference bogus addresses, leading to a number of potential problems. To avoid the above mentioned race condition, platforms such as arm64, riscv and s390 take memory hotplug lock, while dumping kernel page table via the sysfs interface /sys/kernel/debug/kernel_page_tables. Similar race condition exists while checking for pages that might have been marked W+X via /sys/kernel/debug/kernel_page_tables/check_wx_pages which in turn calls ptdump_check_wx(). Instead of solving this race condition again, let's just move the memory hotplug lock inside generic ptdump_check_wx() which will benefit both the scenarios. Drop get_online_mems() and put_online_mems() combination from all existing platform ptdump code paths. Link: https://lkml.kernel.org/r/20250620052427.2092093-1-anshuman.khandual@arm.com Fixes: `bbd6ec605c` ("arm64/mm: Enable memory hot remove") Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Dev Jain <dev.jain@arm.com> Acked-by: Alexander Gordeev <agordeev@linux.ibm.com> [s390] Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2025-08-28 16:28:42 +02:00
arch	mm/ptdump: take the memory hotplug lock inside ptdump_walk_pgd()	2025-08-28 16:28:42 +02:00
block	block: reject invalid operation in submit_bio_noacct	2025-08-28 16:28:40 +02:00
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Documentation	fscrypt: Don't use problematic non-inline crypto engines	2025-08-28 16:28:40 +02:00
drivers	usb: typec: fusb302: cache PD RX state	2025-08-28 16:28:40 +02:00
fs	btrfs: send: make fs_path_len() inline and constify its argument	2025-08-28 16:28:41 +02:00
include	btrfs: constify more pointer parameters	2025-08-28 16:28:41 +02:00
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mm	mm/ptdump: take the memory hotplug lock inside ptdump_walk_pgd()	2025-08-28 16:28:42 +02:00
net	wifi: mac80211: check basic rates validity in sta_link_apply_parameters	2025-08-28 16:28:41 +02:00
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Linux kernel
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There are several guides for kernel developers and users. These guides can
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There are various text files in the Documentation/ subdirectory,
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