Fix for the "kmem {-n|-p}" options on Linux 5.12-rc1 and later kernels that contain commit 1f90a3477df3f ("mm: teach pfn_to_online_page() about ZONE_DEVICE section collisions"). Without the patch, the "kmem -n" option incorrectly shows mem_map addresses containing the flag in bit 5 as part of the virtual address, and also the "kmem -p" option shows page structures at wrong position. With the patch, the "kmem -n" option displays the new "D" state flag. Without the patch: crash> kmem -n ... NR SECTION CODED_MEM_MAP MEM_MAP STATE PFN 1040 ffff9edf3ffd4100 ffffe2bcc0000010 ffffe2bd42000010 PMOE 34078720 ^ ^ crash> kmem -p PAGE PHYSICAL MAPPING INDEX CNT FLAGS ffffe2bd42000010 2080000000 400040 1ffffffff 9961471 dead000000000122 referenced,active,error ffffe2bd42000050 2080001000 800080 1ffffffff 9961471 dead000000000122 referenced,active,error ffffe2bd42000090 2080002000 0 1ffffffff 9961471 dead000000000122 referenced,active,error ^^ With the patch: crash> kmem -n ... NR SECTION CODED_MEM_MAP MEM_MAP STATE PFN 1040 ffff9edf3ffd4100 ffffe2bcc0000000 ffffe2bd42000000 PMOED 34078720 crash> kmem -p PAGE PHYSICAL MAPPING INDEX CNT FLAGS ffffe2bd42000000 2080000000 ffff9ebfc0044100 0 1 97ffffc0000200 slab ffffe2bd42000040 2080001000 ffff9ebfc0044400 0 1 97ffffc0000200 slab ffffe2bd42000080 2080002000 0 0 1 97ffffc0000000 Signed-off-by: Kazuhito Hagio <k-hagio-ab(a)nec.com&gt; --- help.c | 12 ++++++++---- memory.c | 15 +++++++++------ 2 files changed, 17 insertions(+), 10 deletions(-) diff --git a/help.c b/help.c index e0c84087add3..7734281166eb 100644 --- a/help.c +++ b/help.c @@ -6584,10 +6584,14 @@ char *help_kmem[] = { " kernels, the vm_zone_stat, vm_node_stat and vm_numa_stat tables,", " the cumulative page_states counter values if they exist, and/or ", " the cumulative, vm_event_states counter values if they exist.", -" -n display memory node, memory section, and memory block data", -" and state; the state of each memory section state is encoded", -" as \"P\", \"M\", \"O\" and/or \"E\", meaning SECTION_MARKED_PRESENT,", -" SECTION_HAS_MEM_MAP, SECTION_IS_ONLINE and SECTION_IS_EARLY.", +" -n display memory node, memory section, memory block data and state;", +" the state of each memory section is shown as the following flags", +" respectively:", +" \"P\": SECTION_MARKED_PRESENT", +" \"M\": SECTION_HAS_MEM_MAP", +" \"O\": SECTION_IS_ONLINE", +" \"E\": SECTION_IS_EARLY", +" \"D\": SECTION_TAINT_ZONE_DEVICE", " -z displays per-zone memory statistics.", " -o displays each cpu's offset value that is added to per-cpu symbol", " values to translate them into kernel virtual addresses.", diff --git a/memory.c b/memory.c index 8c6bbe409922..7bc9a2cd6d0e 100644 --- a/memory.c +++ b/memory.c @@ -17269,12 +17269,13 @@ nr_to_section(ulong nr) * which results in PFN_SECTION_SHIFT equal 6. * To sum it up, at least 6 bits are available. */ -#define SECTION_MARKED_PRESENT (1UL<<0) -#define SECTION_HAS_MEM_MAP (1UL<<1) -#define SECTION_IS_ONLINE (1UL<<2) -#define SECTION_IS_EARLY (1UL<<3) -#define SECTION_MAP_LAST_BIT (1UL<<4) -#define SECTION_MAP_MASK (~(SECTION_MAP_LAST_BIT-1)) +#define SECTION_MARKED_PRESENT (1UL<<0) +#define SECTION_HAS_MEM_MAP (1UL<<1) +#define SECTION_IS_ONLINE (1UL<<2) +#define SECTION_IS_EARLY (1UL<<3) +#define SECTION_TAINT_ZONE_DEVICE (1UL<<4) +#define SECTION_MAP_LAST_BIT (1UL<<5) +#define SECTION_MAP_MASK (~(SECTION_MAP_LAST_BIT-1)) int @@ -17372,6 +17373,8 @@ fill_mem_section_state(ulong state, char *buf) bufidx += sprintf(buf + bufidx, "%s", "O"); if (state & SECTION_IS_EARLY) bufidx += sprintf(buf + bufidx, "%s", "E"); + if (state & SECTION_TAINT_ZONE_DEVICE) + bufidx += sprintf(buf + bufidx, "%s", "D"); } void -- 2.27.0