[PATCH 4.14 10/91] powerpc/xive: Ignore kmemleak false positives

Greg Kroah-Hartman
2020-09-01T17:09:16Z

From: Alexey Kardashevskiy <aik@ozlabs.ru>

[ Upstream commit f0993c839e95dd6c7f054a1015e693c87e33e4fb ]

xive_native_provision_pages() allocates memory and passes the pointer to
OPAL so kmemleak cannot find the pointer usage in the kernel memory and
produces a false positive report (below) (even if the kernel did scan
OPAL memory, it is unable to deal with __pa() addresses anyway).

This silences the warning.

unreferenced object 0xc000200350c40000 (size 65536):
comm "qemu-system-ppc", pid 2725, jiffies 4294946414 (age 70776.530s)
hex dump (first 32 bytes):
02 00 00 00 50 00 00 00 00 00 00 00 00 00 00 00 ....P...........
01 00 08 07 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<0000000081ff046c>] xive_native_alloc_vp_block+0x120/0x250
[<00000000d555d524>] kvmppc_xive_compute_vp_id+0x248/0x350 [kvm]
[<00000000d69b9c9f>] kvmppc_xive_connect_vcpu+0xc0/0x520 [kvm]
[<000000006acbc81c>] kvm_arch_vcpu_ioctl+0x308/0x580 [kvm]
[<0000000089c69580>] kvm_vcpu_ioctl+0x19c/0xae0 [kvm]
[<00000000902ae91e>] ksys_ioctl+0x184/0x1b0
[<00000000f3e68bd7>] sys_ioctl+0x48/0xb0
[<0000000001b2c127>] system_call_exception+0x124/0x1f0
[<00000000d2b2ee40>] system_call_common+0xe8/0x214

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200612043303.84894-1-aik@ozlabs.ru
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/sysdev/xive/native.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/arch/powerpc/sysdev/xive/native.c b/arch/powerpc/sysdev/xive/native.c
index 30cdcbfa1c04e..b0e96f4b728c1 100644
--- a/arch/powerpc/sysdev/xive/native.c
+++ b/arch/powerpc/sysdev/xive/native.c
@@ -22,6 +22,7 @@
#include <linux/delay.h>
#include <linux/cpumask.h>
#include <linux/mm.h>
+#include <linux/kmemleak.h>

#include <asm/prom.h>
#include <asm/io.h>
@@ -630,6 +631,7 @@ static bool xive_native_provision_pages(void)
pr_err("Failed to allocate provisioning page\n");
return false;
}
+ kmemleak_ignore(p);
opal_xive_donate_page(chip, __pa(p));
}
return true;
--
2.25.1