From: Baoquan He <[email protected]> People reported that when allocating crashkernel memory using the ",high" and ",low" syntax, there were cases where the reservation of the high portion succeeds but the reservation of the low portion fails.
Then kexec can load the kdump kernel successfully, but booting the kdump kernel fails as there's no low memory. The low memory allocation for the kdump kernel can fail on large systems for a couple of reasons. For example, the manually specified crashkernel low memory can be too large and thus no adequate memblock region would be found. Therefore, we try to reserve low memory for the crash kernel *after* the high memory portion has been allocated. If that fails, we free crashkernel high memory too and return. The user can then take measures accordingly. Signed-off-by: Baoquan He <[email protected]> Reviewed-by: Joerg Roedel <[email protected]> Tested-by: Joerg Roedel <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Dave Young <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: [email protected] Cc: Jiri Kosina <[email protected]> Cc: Juergen Gross <[email protected]> Cc: Mark Salter <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: WANG Chao <[email protected]> Cc: x86-ml <[email protected]> Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] [ Massage text. ] Signed-off-by: Borislav Petkov <[email protected]> --- arch/x86/kernel/setup.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index fdb7f2a2d328..1b36839e41eb 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -493,7 +493,7 @@ static void __init memblock_x86_reserve_range_setup_data(void) # define CRASH_KERNEL_ADDR_HIGH_MAX MAXMEM #endif -static void __init reserve_crashkernel_low(void) +static int __init reserve_crashkernel_low(void) { #ifdef CONFIG_X86_64 const unsigned long long alignment = 16<<20; /* 16M */ @@ -522,17 +522,16 @@ static void __init reserve_crashkernel_low(void) } else { /* passed with crashkernel=0,low ? */ if (!low_size) - return; + return 0; } low_base = memblock_find_in_range(low_size, (1ULL<<32), low_size, alignment); if (!low_base) { - if (!auto_set) - pr_info("crashkernel low reservation failed - No suitable area found.\n"); - - return; + pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n", + (unsigned long)(low_size >> 20)); + return -ENOMEM; } memblock_reserve(low_base, low_size); @@ -544,6 +543,7 @@ static void __init reserve_crashkernel_low(void) crashk_low_res.end = low_base + low_size - 1; insert_resource(&iomem_resource, &crashk_low_res); #endif + return 0; } static void __init reserve_crashkernel(void) @@ -595,6 +595,11 @@ static void __init reserve_crashkernel(void) } memblock_reserve(crash_base, crash_size); + if (crash_base >= (1ULL << 32) && reserve_crashkernel_low()) { + memblock_free(crash_base, crash_size); + return; + } + printk(KERN_INFO "Reserving %ldMB of memory at %ldMB " "for crashkernel (System RAM: %ldMB)\n", (unsigned long)(crash_size >> 20), @@ -604,9 +609,6 @@ static void __init reserve_crashkernel(void) crashk_res.start = crash_base; crashk_res.end = crash_base + crash_size - 1; insert_resource(&iomem_resource, &crashk_res); - - if (crash_base >= (1ULL<<32)) - reserve_crashkernel_low(); } #else static void __init reserve_crashkernel(void) -- 2.3.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
