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authorYasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>2014-10-10 02:29:07 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2014-10-10 06:26:00 +0400
commit22880ebe76be421a572b6f004604467c63f281f5 (patch)
tree0ee524463897136db4e313fa97bc080e94f4ac04 /mm/ksm.c
parentd85fbee89f6e67e37ed722adaf085f49b1ce6c50 (diff)
downloadlinux-22880ebe76be421a572b6f004604467c63f281f5.tar.xz
drivers/firmware/memmap.c: don't create memmap sysfs of same firmware_map_entry
By the following commits, we prevented from allocating firmware_map_entry of same memory range: f0093ede: drivers/firmware/memmap.c: don't allocate firmware_map_entry of same memory range 49c8b24d: drivers/firmware/memmap.c: pass the correct argument to firmware_map_find_entry_bootmem() But it's not enough. When PNP0C80 device is added by acpi_scan_init(), memmap sysfses of same firmware_map_entry are created twice as follows: # cat /sys/firmware/memmap/*/start 0x40000000000 0x60000000000 0x4a837000 0x4a83a000 0x4a8b5000 ... 0x40000000000 0x60000000000 ... The flows of the issues are as follows: 1. e820_reserve_resources() allocates firmware_map_entrys of all memory ranges defined in e820. And, these firmware_map_entrys are linked with map_entries list. map_entries -> entry 1 -> ... -> entry N 2. When PNP0C80 device is limited by mem= boot option, acpi_scan_init() added the memory device. In this case, firmware_map_add_hotplug() allocates firmware_map_entry and creates memmap sysfs. map_entries -> entry 1 -> ... -> entry N -> entry N+1 | memmap 1 3. firmware_memmap_init() creates memmap sysfses of firmware_map_entrys linked with map_entries. map_entries -> entry 1 -> ... -> entry N -> entry N+1 | | | memmap 2 memmap N+1 memmap 1 memmap N+2 So while hot removing the PNP0C80 device, kernel panic occurs as follows: BUG: unable to handle kernel paging request at 00000001003e000b IP: sysfs_open_file+0x46/0x2b0 PGD 203a89fe067 PUD 0 Oops: 0000 [#1] SMP ... Call Trace: do_dentry_open+0x1ef/0x2a0 finish_open+0x31/0x40 do_last+0x57c/0x1220 path_openat+0xc2/0x4c0 do_filp_open+0x4b/0xb0 do_sys_open+0xf3/0x1f0 SyS_open+0x1e/0x20 system_call_fastpath+0x16/0x1b The patch adds a check of confirming whether memmap sysfs of firmware_map_entry has been created, and does not create memmap sysfs of same firmware_map_entry. Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Santosh Shilimkar <santosh.shilimkar@ti.com> Cc: Toshi Kani <toshi.kani@hp.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/ksm.c')
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