Messages in this thread | | | Date | Mon, 15 Jan 2024 14:08:21 +0000 | Subject | memblock_reserve for unadded region (was: [PATCH] MIPS: loongson64: fix boot failure) | From | Jiaxun Yang <> |
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Hi mm folks,
Just a quick question, what is the expected behavior of memblock_reserve a region that is not added to memblock with memblock_add?
I'm unable to find any documentation about memblock_reserve in comments and boot-time-mm, but as per my understanding to the code, this should be a legit usage?
In practical we run into uninitialized nid of reserved block problem, should we fix it in our usage, or on memblock side?
Thanks
在 2023/12/25 09:30, Huang Pei 写道: > Since commit 61167ad5fecd("mm: pass nid to reserve_bootmem_region()), > loongson64 booting failed with CONFIG_DEFERRED_STRUCT_PAGE_INIT like > this: > ---------------------------------------------------------------------- > Call Trace: > [<ffffffff8235d088>] reserve_bootmem_region+0xa8/0x184 > [<ffffffff82333940>] memblock_free_all+0x104/0x2a8 > [<ffffffff8231d8e4>] mem_init+0x84/0x94 > [<ffffffff82330958>] mm_core_init+0xf8/0x308 > [<ffffffff82318c38>] start_kernel+0x43c/0x86c > > Code: 10400028 2402fff0 de420000 <dc432880> 0203182b 14600022 > 64420070 00003025 24040003 > > ---[ end trace 0000000000000000 ]--- > Kernel panic - not syncing: Attempted to kill the idle task! > ---[ end Kernel panic - not syncing: Attempted to kill the idle task! ]--- > ---------------------------------------------------------------------- > > The root cause is no memory region "0x0-0x1fffff" paired with > memory-reserved region "0x0-0x1fffff" and "0x0-0xfff", with "memblock > =debug": > > ---------------------------------------------------------------------- > memory[0x0] [0x0000000000200000-0x000000000effffff], > 0x000000000ee00000 bytes on node 0 flags: 0x0 !!!!here > memory[0x1] [0x0000000090000000-0x00000000fdffffff], > 0x000000006e000000 bytes on node 0 flags: 0x0 > memory[0x2] [0x0000000100000000-0x000000027fffffff], > 0x0000000180000000 bytes on node 0 flags: 0x0 > memory[0x3] [0x0000100000000000-0x000010000fffffff], > 0x0000000010000000 bytes on node 1 flags: 0x0 > memory[0x4] [0x0000100090000000-0x000010027fffffff], > 0x00000001f0000000 bytes on node 1 flags: 0x0 > reserved.cnt = 0x1f > reserved[0x0] [0x0000000000000000-0x000000000190c80a], > 0x000000000190c80b bytes flags: 0x0 !!!!oops 0x0-0x1fffff not in memory[0] > reserved[0x1] [0x000000000190c810-0x000000000190eea3], > 0x0000000000002694 bytes flags: 0x0 > ---------------------------------------------------------------------- > > It caused memory-reserved region "0x0-0x1fffff" without valid node id > in "memblock_get_region_node" from "memmap_init_reserved_pages", lead to > "reserve_bootmem_region-> init_reserved_page -> early_pfn_to_nid()" > accessing "node_data" out of bound. > > To fix this bug, we should remove unnecessary memory block reservation. > > +. no need to reserve 0x0-0x1fffff below kernel loading address, since > it is not registered by "memblock_add_node" > > +. no need to reserve 0x0-0xfff for exception handling if it is not > registered by "memblock_add" either. > > Fixes: commit 61167ad5fecd("mm: pass nid to reserve_bootmem_region()) > Signed-off-by: Huang Pei <huangpei@loongson.cn> > --- > arch/mips/kernel/traps.c | 3 ++- > arch/mips/loongson64/numa.c | 2 -- > 2 files changed, 2 insertions(+), 3 deletions(-) > > diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c > index 246c6a6b0261..9b632b4c10c3 100644 > --- a/arch/mips/kernel/traps.c > +++ b/arch/mips/kernel/traps.c > @@ -2007,7 +2007,8 @@ unsigned long vi_handlers[64]; > > void reserve_exception_space(phys_addr_t addr, unsigned long size) > { > - memblock_reserve(addr, size); > + if(memblock_is_region_memory(addr, size)) > + memblock_reserve(addr, size); > } > > void __init *set_except_vector(int n, void *addr) > diff --git a/arch/mips/loongson64/numa.c b/arch/mips/loongson64/numa.c > index 8f61e93c0c5b..0f516dde81da 100644 > --- a/arch/mips/loongson64/numa.c > +++ b/arch/mips/loongson64/numa.c > @@ -130,8 +130,6 @@ static void __init node_mem_init(unsigned int node) > memblock_reserve((node_addrspace_offset | 0xfe000000), > 32 << 20); > > - /* Reserve pfn range 0~node[0]->node_start_pfn */ > - memblock_reserve(0, PAGE_SIZE * start_pfn); > } > } >
-- --- Jiaxun Yang
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