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| author | zhaoyang <huangzhaoyang@gmail.com> | 2019-08-26 04:07:37 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@armlinux.org.uk> | 2019-08-28 23:30:21 +0100 |
| commit | 5b3efa4f1479c91cb8361acef55f9c6662feba57 (patch) | |
| tree | c1453bd7a5ec001ee584f34e2ceab1ede7ad5164 /arch | |
| parent | 69389837171140e2a94c5b8683c08dceaa8c9c8c (diff) | |
| download | linux-5b3efa4f1479c91cb8361acef55f9c6662feba57.tar.bz2 | |
ARM: 8901/1: add a criteria for pfn_valid of arm
pfn_valid can be wrong when parsing a invalid pfn whose phys address
exceeds BITS_PER_LONG as the MSB will be trimed when shifted.
The issue originally arise from bellowing call stack, which corresponding to
an access of the /proc/kpageflags from userspace with a invalid pfn parameter
and leads to kernel panic.
[46886.723249] c7 [<c031ff98>] (stable_page_flags) from [<c03203f8>]
[46886.723264] c7 [<c0320368>] (kpageflags_read) from [<c0312030>]
[46886.723280] c7 [<c0311fb0>] (proc_reg_read) from [<c02a6e6c>]
[46886.723290] c7 [<c02a6e24>] (__vfs_read) from [<c02a7018>]
[46886.723301] c7 [<c02a6f74>] (vfs_read) from [<c02a778c>]
[46886.723315] c7 [<c02a770c>] (SyS_pread64) from [<c0108620>]
(ret_fast_syscall+0x0/0x28)
Signed-off-by: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm/mm/init.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c index 3a65ded832df..b4be3baa83d4 100644 --- a/arch/arm/mm/init.c +++ b/arch/arm/mm/init.c @@ -175,6 +175,11 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max_low, #ifdef CONFIG_HAVE_ARCH_PFN_VALID int pfn_valid(unsigned long pfn) { + phys_addr_t addr = __pfn_to_phys(pfn); + + if (__phys_to_pfn(addr) != pfn) + return 0; + return memblock_is_map_memory(__pfn_to_phys(pfn)); } EXPORT_SYMBOL(pfn_valid); |