[PATCH 4.14 279/284] mm: kmemleak: take a full lowmem check in kmemleak_*_phys()

Greg Kroah-Hartman
2022-04-18T14:04:03Z

From: Patrick Wang <patrick.wang.shcn@gmail.com>

commit 23c2d497de21f25898fbea70aeb292ab8acc8c94 upstream.

The kmemleak_*_phys() apis do not check the address for lowmem's min
boundary, while the caller may pass an address below lowmem, which will
trigger an oops:

# echo scan > /sys/kernel/debug/kmemleak
Unable to handle kernel paging request at virtual address ff5fffffffe00000
Oops [#1]
Modules linked in:
CPU: 2 PID: 134 Comm: bash Not tainted 5.18.0-rc1-next-20220407 #33
Hardware name: riscv-virtio,qemu (DT)
epc : scan_block+0x74/0x15c
ra : scan_block+0x72/0x15c
epc : ffffffff801e5806 ra : ffffffff801e5804 sp : ff200000104abc30
gp : ffffffff815cd4e8 tp : ff60000004cfa340 t0 : 0000000000000200
t1 : 00aaaaaac23954cc t2 : 00000000000003ff s0 : ff200000104abc90
s1 : ffffffff81b0ff28 a0 : 0000000000000000 a1 : ff5fffffffe01000
a2 : ffffffff81b0ff28 a3 : 0000000000000002 a4 : 0000000000000001
a5 : 0000000000000000 a6 : ff200000104abd7c a7 : 0000000000000005
s2 : ff5fffffffe00ff9 s3 : ffffffff815cd998 s4 : ffffffff815d0e90
s5 : ffffffff81b0ff28 s6 : 0000000000000020 s7 : ffffffff815d0eb0
s8 : ffffffffffffffff s9 : ff5fffffffe00000 s10: ff5fffffffe01000
s11: 0000000000000022 t3 : 00ffffffaa17db4c t4 : 000000000000000f
t5 : 0000000000000001 t6 : 0000000000000000
status: 0000000000000100 badaddr: ff5fffffffe00000 cause: 000000000000000d
scan_gray_list+0x12e/0x1a6
kmemleak_scan+0x2aa/0x57e
kmemleak_write+0x32a/0x40c
full_proxy_write+0x56/0x82
vfs_write+0xa6/0x2a6
ksys_write+0x6c/0xe2
sys_write+0x22/0x2a
ret_from_syscall+0x0/0x2

The callers may not quite know the actual address they pass(e.g. from
devicetree). So the kmemleak_*_phys() apis should guarantee the address
they finally use is in lowmem range, so check the address for lowmem's
min boundary.

Link: https://lkml.kernel.org/r/20220413122925.33856-1-patrick.wang.shcn@gmail.com
Signed-off-by: Patrick Wang <patrick.wang.shcn@gmail.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
mm/kmemleak.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -1192,7 +1192,7 @@ EXPORT_SYMBOL(kmemleak_no_scan);
void __ref kmemleak_alloc_phys(phys_addr_t phys, size_t size, int min_count,
gfp_t gfp)
{
- if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
+ if (PHYS_PFN(phys) >= min_low_pfn && PHYS_PFN(phys) < max_low_pfn)
kmemleak_alloc(__va(phys), size, min_count, gfp);
}
EXPORT_SYMBOL(kmemleak_alloc_phys);
@@ -1203,7 +1203,7 @@ EXPORT_SYMBOL(kmemleak_alloc_phys);
*/
void __ref kmemleak_free_part_phys(phys_addr_t phys, size_t size)
{
- if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
+ if (PHYS_PFN(phys) >= min_low_pfn && PHYS_PFN(phys) < max_low_pfn)
kmemleak_free_part(__va(phys), size);
}
EXPORT_SYMBOL(kmemleak_free_part_phys);
@@ -1214,7 +1214,7 @@ EXPORT_SYMBOL(kmemleak_free_part_phys);
*/
void __ref kmemleak_not_leak_phys(phys_addr_t phys)
{
- if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
+ if (PHYS_PFN(phys) >= min_low_pfn && PHYS_PFN(phys) < max_low_pfn)
kmemleak_not_leak(__va(phys));
}
EXPORT_SYMBOL(kmemleak_not_leak_phys);
@@ -1225,7 +1225,7 @@ EXPORT_SYMBOL(kmemleak_not_leak_phys);
*/
void __ref kmemleak_ignore_phys(phys_addr_t phys)
{
- if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
+ if (PHYS_PFN(phys) >= min_low_pfn && PHYS_PFN(phys) < max_low_pfn)
kmemleak_ignore(__va(phys));
}
EXPORT_SYMBOL(kmemleak_ignore_phys);