6.18-stable review patch. If anyone has any objections, please let me know.
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From: Jianpeng Chang jianpeng.chang.cn@windriver.com
[ Upstream commit 3e8ade58b71b48913d21b647b2089e03e81f117e ]
Commit 8a6e02d0c00e ("of: reserved_mem: Restructure how the reserved memory regions are processed") changed the processing order of reserved memory regions, causing elfcorehdr to overlap with dynamically allocated reserved memory regions during kdump kernel boot.
The issue occurs because: 1. kexec-tools allocates elfcorehdr in the last crashkernel reserved memory region and passes it to the second kernel 2. The problematic commit moved dynamic reserved memory allocation (like bman-fbpr) to occur during fdt_scan_reserved_mem(), before elfcorehdr reservation in fdt_reserve_elfcorehdr() 3. bman-fbpr with 16MB alignment requirement can get allocated at addresses that overlap with the elfcorehdr location 4. When fdt_reserve_elfcorehdr() tries to reserve elfcorehdr memory, overlap detection identifies the conflict and skips reservation 5. kdump kernel fails with "Unable to handle kernel paging request" because elfcorehdr memory is not properly reserved
The boot log: Before 8a6e02d0c00e: OF: fdt: Reserving 1 KiB of memory at 0xf4fff000 for elfcorehdr OF: reserved mem: 0xf3000000..0xf3ffffff bman-fbpr
After 8a6e02d0c00e: OF: reserved mem: 0xf4000000..0xf4ffffff bman-fbpr OF: fdt: elfcorehdr is overlapped
Fix this by ensuring elfcorehdr reservation occurs before dynamic reserved memory allocation.
Fixes: 8a6e02d0c00e ("of: reserved_mem: Restructure how the reserved memory regions are processed") Signed-off-by: Jianpeng Chang jianpeng.chang.cn@windriver.com Link: https://patch.msgid.link/20251205015934.700016-1-jianpeng.chang.cn@windriver... Signed-off-by: Rob Herring (Arm) robh@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/of/fdt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c index fdaee4906836..3851ce244585 100644 --- a/drivers/of/fdt.c +++ b/drivers/of/fdt.c @@ -503,8 +503,8 @@ void __init early_init_fdt_scan_reserved_mem(void) if (!initial_boot_params) return;
- fdt_scan_reserved_mem(); fdt_reserve_elfcorehdr(); + fdt_scan_reserved_mem();
/* Process header /memreserve/ fields */ for (n = 0; ; n++) {