[PATCH 4.19 06/79] Revert "mm: kmemleak: take a full lowmem check in kmemleak_*_phys()"

Greg Kroah-Hartman
2022-09-13T15:26:49Z

From: Yee Lee <yee.lee@mediatek.com>

This reverts commit 23c2d497de21f25898fbea70aeb292ab8acc8c94.

Commit 23c2d497de21 ("mm: kmemleak: take a full lowmem check in
kmemleak_*_phys()") brought false leak alarms on some archs like arm64
that does not init pfn boundary in early booting. The final solution
lands on linux-6.0: commit 0c24e061196c ("mm: kmemleak: add rbtree and
store physical address for objects allocated with PA").

Revert this commit before linux-6.0. The original issue of invalid PA
can be mitigated by additional check in devicetree.

The false alarm report is as following: Kmemleak output: (Qemu/arm64)
unreferenced object 0xffff0000c0170a00 (size 128):
comm "swapper/0", pid 1, jiffies 4294892404 (age 126.208s)
hex dump (first 32 bytes):
62 61 73 65 00 00 00 00 00 00 00 00 00 00 00 00 base............
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<(____ptrval____)>] __kmalloc_track_caller+0x1b0/0x2e4
[<(____ptrval____)>] kstrdup_const+0x8c/0xc4
[<(____ptrval____)>] kvasprintf_const+0xbc/0xec
[<(____ptrval____)>] kobject_set_name_vargs+0x58/0xe4
[<(____ptrval____)>] kobject_add+0x84/0x100
[<(____ptrval____)>] __of_attach_node_sysfs+0x78/0xec
[<(____ptrval____)>] of_core_init+0x68/0x104
[<(____ptrval____)>] driver_init+0x28/0x48
[<(____ptrval____)>] do_basic_setup+0x14/0x28
[<(____ptrval____)>] kernel_init_freeable+0x110/0x178
[<(____ptrval____)>] kernel_init+0x20/0x1a0
[<(____ptrval____)>] ret_from_fork+0x10/0x20

This pacth is also applicable to linux-5.17.y/linux-5.18.y/linux-5.19.y

Cc: <stable@vger.kernel.org>
Signed-off-by: Yee Lee <yee.lee@mediatek.com>
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
@@ -1196,7 +1196,7 @@ EXPORT_SYMBOL(kmemleak_no_scan);
void __ref kmemleak_alloc_phys(phys_addr_t phys, size_t size, int min_count,
gfp_t gfp)
{
- if (PHYS_PFN(phys) >= min_low_pfn && PHYS_PFN(phys) < max_low_pfn)
+ if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
kmemleak_alloc(__va(phys), size, min_count, gfp);
}
EXPORT_SYMBOL(kmemleak_alloc_phys);
@@ -1210,7 +1210,7 @@ EXPORT_SYMBOL(kmemleak_alloc_phys);
*/
void __ref kmemleak_free_part_phys(phys_addr_t phys, size_t size)
{
- if (PHYS_PFN(phys) >= min_low_pfn && PHYS_PFN(phys) < max_low_pfn)
+ if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
kmemleak_free_part(__va(phys), size);
}
EXPORT_SYMBOL(kmemleak_free_part_phys);
@@ -1222,7 +1222,7 @@ EXPORT_SYMBOL(kmemleak_free_part_phys);
*/
void __ref kmemleak_not_leak_phys(phys_addr_t phys)
{
- if (PHYS_PFN(phys) >= min_low_pfn && PHYS_PFN(phys) < max_low_pfn)
+ if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
kmemleak_not_leak(__va(phys));
}
EXPORT_SYMBOL(kmemleak_not_leak_phys);
@@ -1234,7 +1234,7 @@ EXPORT_SYMBOL(kmemleak_not_leak_phys);
*/
void __ref kmemleak_ignore_phys(phys_addr_t phys)
{
- if (PHYS_PFN(phys) >= min_low_pfn && PHYS_PFN(phys) < max_low_pfn)
+ if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
kmemleak_ignore(__va(phys));
}
EXPORT_SYMBOL(kmemleak_ignore_phys);