From: Hari Bathini hbathini@linux.vnet.ibm.com
[ Upstream commit a77af552ccc9d4d54459a39f9e5f7ad307aeb4f9 ]
fadump sets up crash memory ranges to be used for creating PT_LOAD program headers in elfcore header. Memory chunk RMA_START through boot memory area size is added as the first memory range because firmware, at the time of crash, moves this memory chunk to different location specified during fadump registration making it necessary to create a separate program header for it with the correct offset. This memory chunk is skipped while setting up the remaining memory ranges. But currently, there is possibility that some of this memory may have duplicate entries like when it is hot-removed and added again. Ensure that no two memory ranges represent the same memory.
When 5 lmbs are hot-removed and then hot-plugged before registering fadump, here is how the program headers in /proc/vmcore exported by fadump look like
without this change:
Program Headers: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flags Align NOTE 0x0000000000010000 0x0000000000000000 0x0000000000000000 0x0000000000001894 0x0000000000001894 0 LOAD 0x0000000000021020 0xc000000000000000 0x0000000000000000 0x0000000040000000 0x0000000040000000 RWE 0 LOAD 0x0000000040031020 0xc000000000000000 0x0000000000000000 0x0000000010000000 0x0000000010000000 RWE 0 LOAD 0x0000000050040000 0xc000000010000000 0x0000000010000000 0x0000000050000000 0x0000000050000000 RWE 0 LOAD 0x00000000a0040000 0xc000000060000000 0x0000000060000000 0x000000019ffe0000 0x000000019ffe0000 RWE 0
and with this change:
Program Headers: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flags Align NOTE 0x0000000000010000 0x0000000000000000 0x0000000000000000 0x0000000000001894 0x0000000000001894 0 LOAD 0x0000000000021020 0xc000000000000000 0x0000000000000000 0x0000000040000000 0x0000000040000000 RWE 0 LOAD 0x0000000040030000 0xc000000040000000 0x0000000040000000 0x0000000020000000 0x0000000020000000 RWE 0 LOAD 0x0000000060030000 0xc000000060000000 0x0000000060000000 0x000000019ffe0000 0x000000019ffe0000 RWE 0
Signed-off-by: Hari Bathini hbathini@linux.vnet.ibm.com Reviewed-by: Mahesh J Salgaonkar mahesh@linux.vnet.ibm.com Signed-off-by: Michael Ellerman mpe@ellerman.id.au Signed-off-by: Sasha Levin alexander.levin@microsoft.com --- arch/powerpc/kernel/fadump.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c index 26d091a1a54c..5df362630ffc 100644 --- a/arch/powerpc/kernel/fadump.c +++ b/arch/powerpc/kernel/fadump.c @@ -812,8 +812,19 @@ static void fadump_setup_crash_memory_ranges(void) for_each_memblock(memory, reg) { start = (unsigned long long)reg->base; end = start + (unsigned long long)reg->size; - if (start == RMA_START && end >= fw_dump.boot_memory_size) - start = fw_dump.boot_memory_size; + + /* + * skip the first memory chunk that is already added (RMA_START + * through boot_memory_size). This logic needs a relook if and + * when RMA_START changes to a non-zero value. + */ + BUILD_BUG_ON(RMA_START != 0); + if (start < fw_dump.boot_memory_size) { + if (end > fw_dump.boot_memory_size) + start = fw_dump.boot_memory_size; + else + continue; + }
/* add this range excluding the reserved dump area. */ fadump_exclude_reserved_area(start, end);