Pull memblock updates from Mike Rapoport:
- improve debuggability of reserve_mem kernel parameter handling with
print outs in case of a failure and debugfs info showing what was
actually reserved
- Make memblock_free_late() and free_reserved_area() use the same core
logic for freeing the memory to buddy and ensure it takes care of
updating memblock arrays when ARCH_KEEP_MEMBLOCK is enabled.
* tag 'memblock-v7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock:
x86/alternative: delay freeing of smp_locks section
memblock: warn when freeing reserved memory before memory map is initialized
memblock, treewide: make memblock_free() handle late freeing
memblock: make free_reserved_area() update memblock if ARCH_KEEP_MEMBLOCK=y
memblock: extract page freeing from free_reserved_area() into a helper
memblock: make free_reserved_area() more robust
mm: move free_reserved_area() to mm/memblock.c
powerpc: opal-core: pair alloc_pages_exact() with free_pages_exact()
powerpc: fadump: pair alloc_pages_exact() with free_pages_exact()
memblock: reserve_mem: fix end caclulation in reserve_mem_release_by_name()
memblock: move reserve_bootmem_range() to memblock.c and make it static
memblock: Add reserve_mem debugfs info
memblock: Print out errors on reserve_mem parser
Reduce 22 declarations of empty_zero_page to 3 and 23 declarations of
ZERO_PAGE() to 4.
Every architecture defines empty_zero_page that way or another, but for the
most of them it is always a page aligned page in BSS and most definitions
of ZERO_PAGE do virt_to_page(empty_zero_page).
Move Linus vetted x86 definition of empty_zero_page and ZERO_PAGE() to the
core MM and drop these definitions in architectures that do not implement
colored zero page (MIPS and s390).
ZERO_PAGE() remains a macro because turning it to a wrapper for a static
inline causes severe pain in header dependencies.
For the most part the change is mechanical, with these being noteworthy:
* alpha: aliased empty_zero_page with ZERO_PGE that was also used for boot
parameters. Switching to a generic empty_zero_page removes the aliasing
and keeps ZERO_PGE for boot parameters only
* arm64: uses __pa_symbol() in ZERO_PAGE() so that definition of
ZERO_PAGE() is kept intact.
* m68k/parisc/um: allocated empty_zero_page from memblock,
although they do not support zero page coloring and having it in BSS
will work fine.
* sparc64 can have empty_zero_page in BSS rather allocate it, but it
can't use virt_to_page() for BSS. Keep it's definition of ZERO_PAGE()
but instead of allocating it, make mem_map_zero point to
empty_zero_page.
* sh: used empty_zero_page for boot parameters at the very early boot.
Rename the parameters page to boot_params_page and let sh use the generic
empty_zero_page.
* hexagon: had an amusing comment about empty_zero_page
/* A handy thing to have if one has the RAM. Declared in head.S */
that unfortunately had to go :)
Link: https://lkml.kernel.org/r/20260211103141.3215197-4-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: Helge Deller <deller@gmx.de> [parisc]
Tested-by: Helge Deller <deller@gmx.de> [parisc]
Reviewed-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Magnus Lindholm <linmag7@gmail.com> [alpha]
Acked-by: Dinh Nguyen <dinguyen@kernel.org> [nios2]
Acked-by: Andreas Larsson <andreas@gaisler.com> [sparc]
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: "Borislav Petkov (AMD)" <bp@alien8.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
reserve_bootmem_region() is only called from
memmap_init_reserved_pages() and it was in mm/mm_init.c because of its
dependecies on static init_deferred_page().
Since init_deferred_page() is not static anymore, move
reserve_bootmem_region(), rename it to memmap_init_reserved_range() and
make it static.
Update the comment describing it to better reflect what the function
does and drop bogus comment about reserved pages in free_bootmem_page().
Update memblock test stubs to reflect the core changes.
Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Reviewed-by: David Hildenbrand (Arm) <david@kernel.org>
Link: https://patch.msgid.link/20260323072042.3651061-1-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Commit d49004c5f0 ("arch, mm: consolidate initialization of nodes, zones
and memory map") moved free_area_init() from setup_arch() to
mm_core_init_early(), which runs after setup_arch() returns.
This changed the ordering relative to init_cpu_to_node() on x86. Before
the commit, free_area_init() ran during paging_init() (called from
setup_arch()) *before* init_cpu_to_node(). After the commit, it runs
*after* init_cpu_to_node().
On machines with memoryless NUMA nodes (e.g., node 0 has CPUs but no
memory), this causes a NULL pointer dereference:
1. numa_register_nodes() skips memoryless nodes: no alloc_node_data()
and no node_set_online() for them.
2. init_cpu_to_node() sets memoryless nodes online (they have CPUs)
but does not allocate NODE_DATA.
3. free_area_init() checks "if (!node_online(nid))" to decide whether
to call alloc_offline_node_data(). Since the memoryless node is now
online, the allocation is skipped, leaving NODE_DATA(nid) == NULL.
4. The immediate "pgdat = NODE_DATA(nid)" dereferences NULL.
The crash happens before console_init(), so no output is visible without
earlyprintk. With earlyprintk enabled, the following panic is observed:
BUG: unable to handle page fault for address: 000000000002a1e0
Oops: Oops: 0000 [#1] SMP NOPTI
RIP: 0010:free_area_init_node+0x3a/0x540
Call Trace:
<TASK>
free_area_init+0x331/0x4e0
start_kernel+0x69/0x4a0
x86_64_start_reservations+0x24/0x30
x86_64_start_kernel+0x125/0x130
common_startup_64+0x13e/0x148
</TASK>
Kernel panic - not syncing: Attempted to kill the idle task!
Fix this by checking "if (!NODE_DATA(nid))" instead of "if
(!node_online(nid))". This directly tests whether the per-node data
structure needs to be allocated, regardless of the node's online status.
This change is also safe for non-x86 architectures as they all allocate
NODE_DATA for every node including memoryless ones, so the check simply
evaluates to false with no change in behavior.
Link: https://lkml.kernel.org/r/20260222115702.3659-1-ming.lei@redhat.com
Fixes: d49004c5f0 ("arch, mm: consolidate initialization of nodes, zones and memory map")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Pull memblock updates from Mike Rapoport:
- update tools/include/linux/mm.h to fix memblock tests compilation
- drop redundant struct page* parameter from memblock_free_pages() and
get struct page from the pfn
- add underflow detection for size calculation in memtest and warn
about underflow when VM_DEBUG is enabled
* tag 'memblock-v7.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock:
mm/memtest: add underflow detection for size calculation
memblock: drop redundant 'struct page *' argument from memblock_free_pages()
memblock test: include <linux/sizes.h> from tools mm.h stub
Commit 3acb913c9d ("mm/mm_init: use deferred_init_memmap_chunk() in
deferred_grow_zone()") made deferred_grow_zone() call
deferred_init_memmap_chunk() within a pgdat_resize_lock() critical section
with irqs disabled. It did check for irqs_disabled() in
deferred_init_memmap_chunk() to avoid calling cond_resched(). For a
PREEMPT_RT kernel build, however, spin_lock_irqsave() does not disable
interrupt but rcu_read_lock() is called. This leads to the following bug
report.
BUG: sleeping function called from invalid context at mm/mm_init.c:2091
in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 1, name: swapper/0
preempt_count: 0, expected: 0
RCU nest depth: 1, expected: 0
3 locks held by swapper/0/1:
#0: ffff80008471b7a0 (sched_domains_mutex){+.+.}-{4:4}, at: sched_domains_mutex_lock+0x28/0x40
#1: ffff003bdfffef48 (&pgdat->node_size_lock){+.+.}-{3:3}, at: deferred_grow_zone+0x140/0x278
#2: ffff800084acf600 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1b4/0x408
CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Tainted: G W 6.19.0-rc6-test #1 PREEMPT_{RT,(full)
}
Tainted: [W]=WARN
Call trace:
show_stack+0x20/0x38 (C)
dump_stack_lvl+0xdc/0xf8
dump_stack+0x1c/0x28
__might_resched+0x384/0x530
deferred_init_memmap_chunk+0x560/0x688
deferred_grow_zone+0x190/0x278
_deferred_grow_zone+0x18/0x30
get_page_from_freelist+0x780/0xf78
__alloc_frozen_pages_noprof+0x1dc/0x348
alloc_slab_page+0x30/0x110
allocate_slab+0x98/0x2a0
new_slab+0x4c/0x80
___slab_alloc+0x5a4/0x770
__slab_alloc.constprop.0+0x88/0x1e0
__kmalloc_node_noprof+0x2c0/0x598
__sdt_alloc+0x3b8/0x728
build_sched_domains+0xe0/0x1260
sched_init_domains+0x14c/0x1c8
sched_init_smp+0x9c/0x1d0
kernel_init_freeable+0x218/0x358
kernel_init+0x28/0x208
ret_from_fork+0x10/0x20
Fix it adding a new argument to deferred_init_memmap_chunk() to explicitly
tell it if cond_resched() is allowed or not instead of relying on some
current state information which may vary depending on the exact kernel
configuration options that are enabled.
Link: https://lkml.kernel.org/r/20260122184343.546627-1-longman@redhat.com
Fixes: 3acb913c9d ("mm/mm_init: use deferred_init_memmap_chunk() in deferred_grow_zone()")
Signed-off-by: Waiman Long <longman@redhat.com>
Suggested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: <stable@vger.kernrl.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Use bool for 'hashdist' and replace simple_strtoul() with kstrtobool() for
parsing the 'hashdist=' boot parameter. Unlike simple_strtoul(), which
returns an unsigned long, kstrtobool() converts the string directly to
bool and avoids implicit casting.
Check the return value of kstrtobool() and reject invalid values. This
adds error handling while preserving behavior for existing values, and
removes use of the deprecated simple_strtoul() helper. The current code
silently sets 'hashdist = 0' if parsing fails, instead of leaving the
default value (HASHDIST_DEFAULT) unchanged.
Additionally, kstrtobool() accepts common boolean strings such as "on" and
"off".
Link: https://lkml.kernel.org/r/20251217110214.50807-1-thorsten.blum@linux.dev
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
memblock_free_pages() currently takes both a struct page * and the
corresponding PFN. The page pointer is always derived from the PFN at
call sites (pfn_to_page(pfn)), making the parameter redundant and also
allowing accidental mismatches between the two arguments.
Simplify the interface by removing the struct page * argument and
deriving the page locally from the PFN, after the deferred struct page
initialization check. This keeps the behavior unchanged while making
the helper harder to misuse.
Signed-off-by: Shengming Hu <hu.shengming@zte.com.cn>
Reviewed-by: David Hildenbrand (Red Hat) <david@kernel.org>
Link: https://patch.msgid.link/tencent_F741CE6ECC49EE099736685E60C0DBD4A209@qq.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Pull memblock update from Mike Rapoport:
"Introduce a 'check_pages' boot parameter to decouple simple checks for
page state on allocation and free from CONFIG_DEBUG_VM.
This allows enabling page checking without building kernel with
CONFIG_DEBUG_VM or forcing init_on_{alloc, free} or other heavier
mechanisms"
* tag 'memblock-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock:
mm/mm_init: Introduce a boot parameter for check_pages
Use-after-free and double-free bugs can be very difficult to track down.
The kernel is good at tracking these and preventing bad pages from being
used/created through simple checks gated behind "check_pages_enabled".
Currently, the only ways to enable this flag is by building with
CONFIG_DEBUG_VM, or as a side effect of other checks such as
init_on_{alloc, free}, page_poisoning, or debug_pagealloc among others.
These solutions are powerful, but may often be too coarse in balancing
the performance vs. safety that a user may want, particularly in
latency-sensitive production environments.
Introduce a new boot parameter "check_pages", which enables page checking
with no other side effects. It takes kstrbool-able inputs as an argument
(i.e. 0/1, true/false, on/off, ...). This patch is backwards-compatible;
setting CONFIG_DEBUG_VM still enables page checking.
Acked-by: SeongJae Park <sj@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Link: https://patch.msgid.link/20251201180739.2330474-1-joshua.hahnjy@gmail.com
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
When emitting the order of the allocation for a hash table,
alloc_large_system_hash() unconditionally subtracts PAGE_SHIFT from log
base 2 of the allocation size. This is not correct if the allocation size
is smaller than a page, and yields a negative value for the order as seen
below:
TCP established hash table entries: 32 (order: -4, 256 bytes, linear) TCP
bind hash table entries: 32 (order: -2, 1024 bytes, linear)
Use get_order() to compute the order when emitting the hash table
information to correctly handle cases where the allocation size is smaller
than a page:
TCP established hash table entries: 32 (order: 0, 256 bytes, linear) TCP
bind hash table entries: 32 (order: 0, 1024 bytes, linear)
Link: https://lkml.kernel.org/r/20251028191020.413002-1-isaacmanjarres@google.com
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Isaac J. Manjarres <isaacmanjarres@google.com>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Pull mm-init update from Mike Rapoport:
"Simplify deferred initialization of struct pages
Refactor and simplify deferred initialization of the memory map.
Beside the negative diffstat it gives 3ms (55ms vs 58ms) reduction in
the initialization of deferred pages on single node system with 64GiB
of RAM"
* tag 'memblock-v6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock:
memblock: drop for_each_free_mem_pfn_range_in_zone_from()
mm/mm_init: drop deferred_init_maxorder()
mm/mm_init: deferred_init_memmap: use a job per zone
mm/mm_init: use deferred_init_memmap_chunk() in deferred_grow_zone()
Grepping for "prep_compound_page" leaves on clueless how devdax gets its
compound pages initialized.
Let's add a comment that might help finding this open-coded
prep_compound_page() initialization more easily.
Further, let's be less smart about the ordering of initialization and just
perform the prep_compound_head() call after all tail pages were
initialized: just like prep_compound_page() does.
No need for a comment to describe the initialization order: again, just
like prep_compound_page().
Link: https://lkml.kernel.org/r/20250901150359.867252-10-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
