From 4ccae23609f589dd69a593f457f76ee8b0e2d4e0 Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Fri, 19 Apr 2024 21:59:13 +1000 Subject: [PATCH] powerpc/dart: Drop unnecessary call to kmemleak_no_scan() Erhard reported that kmemleak was showing a warning at boot: kmemleak: Not scanning unknown object at 0xc00000007f000000 CPU: 0 PID: 0 Comm: swapper Not tainted 5.19.0-rc3-PMacG5+ #2 Call Trace: .dump_stack_lvl+0x7c/0xc4 (unreliable) .kmemleak_no_scan+0xe0/0x100 .iommu_init_early_dart+0x2f0/0x924 .pmac_probe+0x1b0/0x20c .setup_arch+0x1b8/0x674 .start_kernel+0xdc/0xb74 start_here_common+0x1c/0x44 DART table allocated at: (____ptrval____) Which he bisected to a change in kmemleak, commit 23c2d497de21 ("mm: kmemleak: take a full lowmem check in kmemleak_*_phys()"). Because pmac_probe() is called before mem_topology_setup(), the min/ max PFN variables are still zero. That causes kmemleak_alloc_phys() to ignore the allocation, because the checks against the PFN fail. Then kmemleak_no_scan() can't find the allocation and prints warning. Given that kmemleak_alloc_phys() is ignoring the allocation to begin with, there's no need to call kmemleak_no_scan() at all, which avoids the warning. Reported-by: Erhard Furtner Closes: https://lore.kernel.org/all/bug-216156-206035@https.bugzilla.kernel.org%2F/ Signed-off-by: Michael Ellerman Link: https://msgid.link/20240419115913.3317575-1-mpe@ellerman.id.au --- arch/powerpc/sysdev/dart_iommu.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/arch/powerpc/sysdev/dart_iommu.c b/arch/powerpc/sysdev/dart_iommu.c index 98096bbfd62e8..c0d10c149661c 100644 --- a/arch/powerpc/sysdev/dart_iommu.c +++ b/arch/powerpc/sysdev/dart_iommu.c @@ -24,7 +24,6 @@ #include #include #include -#include #include #include #include @@ -243,9 +242,6 @@ static void __init allocate_dart(void) if (!dart_tablebase) panic("Failed to allocate 16MB below 2GB for DART table\n"); - /* There is no point scanning the DART space for leaks*/ - kmemleak_no_scan((void *)dart_tablebase); - /* Allocate a spare page to map all invalid DART pages. We need to do * that to work around what looks like a problem with the HT bridge * prefetching into invalid pages and corrupting data -- 2.30.2