From: Qian Cai <cai@xxxxxx>
No matching commit upstream, but the issue being addressed no longer
exists after commit 80424b02d42b ("efi: Reduce the amount of memblock
reservations for persistent allocations") was merged for the 5.0 cycle.
unreferenced object 0xffff8096c1acf580 (size 128):
comm "swapper/63", pid 0, jiffies 4294937418 (age 1201.230s)
hex dump (first 32 bytes):
80 87 b5 c1 96 00 00 00 00 00 cc c2 16 00 00 00 ................
00 00 01 00 00 00 00 00 6b 6b 6b 6b 6b 6b 6b 6b ........kkkkkkkk
backtrace:
[<000000001d2549ba>] kmem_cache_alloc_trace+0x430/0x500
[<0000000093a6dfab>] efi_mem_reserve_persistent+0x50/0xf8
[<000000000a730828>] its_cpu_init_lpis+0x394/0x4b8
[<00000000edf04e07>] its_cpu_init+0x104/0x150
[<000000004d0342c5>] gic_starting_cpu+0x34/0x40
[<000000005d9da772>] cpuhp_invoke_callback+0x228/0x1d68
[<0000000061eace9b>] notify_cpu_starting+0xc0/0x118
[<0000000048bc2dc5>] secondary_start_kernel+0x23c/0x3b0
[<0000000015137d6a>] 0xffffffffffffffff
efi_mem_reserve_persistent+0x50/0xf8:
kmalloc at include/linux/slab.h:546
(inlined by) efi_mem_reserve_persistent at drivers/firmware/efi/efi.c:979
This line,
rsv = kmalloc(sizeof(*rsv), GFP_ATOMIC);
Kmemleak has a known limitation that can only track pointers in the kernel
virtual space. Hence, it will report false positives due to "rsv" will only
reference to other physical addresses,
rsv->next = efi_memreserve_root->next;
efi_memreserve_root->next = __pa(rsv);
Fixes: a23d3bb05ccb ("efi: add API to reserve memory persistently across ...")
Cc: <stable@xxxxxxxxxxxxxxx> # v4.20
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Qian Cai <cai@xxxxxx>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
drivers/firmware/efi/efi.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 415849bab233..7fcfe8a7ae98 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -31,6 +31,7 @@
#include <linux/acpi.h>
#include <linux/ucs2_string.h>
#include <linux/memblock.h>
+#include <linux/kmemleak.h>
#include <asm/early_ioremap.h>
@@ -1000,6 +1001,8 @@ int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
if (!rsv)
return -ENOMEM;
+ kmemleak_ignore(rsv);
+
rsv->base = addr;
rsv->size = size;
--
2.20.1
