The patch titled
Subject: drivers/firmware/memmap.c: don't allocate firmware_map_entry of same memory range
has been removed from the -mm tree. Its filename was
dont-allocate-firmware_map_entry-of-same-memory-range.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
Subject: drivers/firmware/memmap.c: don't allocate firmware_map_entry of same memory range
When limiting memory by mem= and ACPI DSDT table has PNP0C80,
firmware_map_entrys of same memory range are allocated and memmap X
sysfses which have same memory range are created as follows:
# cat /sys/firmware/memmap/0/*
0x407ffffffff
0x40000000000
System RAM
# cat /sys/firmware/memmap/33/*
0x407ffffffff
0x40000000000
System RAM
# cat /sys/firmware/memmap/35/*
0x407ffffffff
0x40000000000
System RAM
In this case, when hot-removing memory, kernel panic occurs, showing
following call trace:
BUG: unable to handle kernel paging request at 00000001003e000b
IP: [<ffffffff81225c26>] sysfs_open_file+0x46/0x2b0
PGD 203a89fe067 PUD 0
Oops: 0000 [#1] SMP
...
Call Trace:
[<ffffffff811ad95f>] do_dentry_open+0x1ef/0x2a0
[<ffffffff811bba32>] ? __inode_permission+0x52/0xc0
[<ffffffff81225be0>] ? sysfs_schedule_callback+0x1c0/0x1c0
[<ffffffff811ada41>] finish_open+0x31/0x40
[<ffffffff811bf6ac>] do_last+0x57c/0x1220
[<ffffffff8119529e>] ? kmem_cache_alloc_trace+0x1ce/0x1f0
[<ffffffff811c0412>] path_openat+0xc2/0x4c0
[<ffffffff81167e2c>] ? tlb_flush_mmu.part.53+0x4c/0x90
[<ffffffff811c102b>] do_filp_open+0x4b/0xb0
[<ffffffff811cd827>] ? __alloc_fd+0xa7/0x130
[<ffffffff811aeed3>] do_sys_open+0xf3/0x1f0
[<ffffffff811aefee>] SyS_open+0x1e/0x20
[<ffffffff815f2199>] system_call_fastpath+0x16/0x1b
The problem occurs as follows:
When calling e820_reserve_resources(), firmware_map_entrys of all
e820 memory map are allocated. And all firmware_map_entrys is added
map_entries list as follows:
map_entries
-> +--- entry A --------+ -> ...
| start 0x407ffffffff|
| end 0x40000000000|
| type System RAM |
+--------------------+
After that, if ACPI DSDT table has PNP0C80 and the memory range is
limited by mem=, the PNP0C80 is hot-added. Then firmware_map_entry of
PNP0C80 is allocated and added map_entries list as follows:
map_entries
-> +--- entry A --------+ -> ... -> +--- entry B --------+
| start 0x407ffffffff| | start 0x407ffffffff|
| end 0x40000000000| | end 0x40000000000|
| type System RAM | | type System RAM |
+--------------------+ +--------------------+
Then memmap 0 sysfs for entry B is created.
After that, firmware_memmap_init() creates memmap sysfses of all
firmware_map_entrys in map_entries list. As a result, memmap 33 sysfs for
entry A and memmap 35 sysfs for entry B are created. But kobject of entry
B has been used by memmap 0 sysfs. So when creating memmap 35 sysfs, the
kobject is broken.
If hot-removing memory, memmap 0 sysfs is destroyed and kobject of memmap
0 sysfs is freed. But the kobject can be accessed via memmap 35 sysfs.
So when open memmap 35 sysfs, kernel panic occurs.
This patch checks whether there is firmware_map_entry of same memory range
in map_entries list and don't allocate firmware_map_entry of same memroy
range.
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
Cc: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
Cc: Toshi Kani <toshi.kani@xxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/firmware/memmap.c | 4 ++++
1 file changed, 4 insertions(+)
diff -puN drivers/firmware/memmap.c~dont-allocate-firmware_map_entry-of-same-memory-range drivers/firmware/memmap.c
--- a/drivers/firmware/memmap.c~dont-allocate-firmware_map_entry-of-same-memory-range
+++ a/drivers/firmware/memmap.c
@@ -286,6 +286,10 @@ int __meminit firmware_map_add_hotplug(u
{
struct firmware_map_entry *entry;
+ entry = firmware_map_find_entry(start, end - 1, type);
+ if (entry)
+ return 0;
+
entry = firmware_map_find_entry_bootmem(start, end - 1, type);
if (!entry) {
entry = kzalloc(sizeof(struct firmware_map_entry), GFP_ATOMIC);
_
Patches currently in -mm which might be from isimatu.yasuaki@xxxxxxxxxxxxxx are
origin.patch
x86mem-hotplug-pass-sync_global_pgds-a-correct-argument-in-remove_pagetable.patch
x86mem-hotplug-modify-pgd-entry-when-removing-memory.patch
x86-numa-setup_node_data-drop-dead-code-and-rename-function.patch
x86-numa-setup_node_data-drop-dead-code-and-rename-function-v2.patch
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