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authorzhaoyang <huangzhaoyang@gmail.com>2019-08-26 04:07:37 +0100
committerRussell King <rmk+kernel@armlinux.org.uk>2019-08-28 23:30:21 +0100
commit5b3efa4f1479c91cb8361acef55f9c6662feba57 (patch)
treec1453bd7a5ec001ee584f34e2ceab1ede7ad5164 /arch/arm/mm/init.c
parent69389837171140e2a94c5b8683c08dceaa8c9c8c (diff)
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/arm/mm/init.c')
-rw-r--r--arch/arm/mm/init.c5
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);