On x86_32 Qemu machine with 1GB memory, the cmdline "crashkernel=1G,high"
will cause system stall as below:
ACPI: Reserving FACP table memory at [mem 0x3ffe18b8-0x3ffe192b]
ACPI: Reserving DSDT table memory at [mem 0x3ffe0040-0x3ffe18b7]
ACPI: Reserving FACS table memory at [mem 0x3ffe0000-0x3ffe003f]
ACPI: Reserving APIC table memory at [mem 0x3ffe192c-0x3ffe19bb]
ACPI: Reserving HPET table memory at [mem 0x3ffe19bc-0x3ffe19f3]
ACPI: Reserving WAET table memory at [mem 0x3ffe19f4-0x3ffe1a1b]
143MB HIGHMEM available.
879MB LOWMEM available.
mapped low ram: 0 - 36ffe000
low ram: 0 - 36ffe000
(stall here)
The reason is that the CRASH_ADDR_LOW_MAX is equal to CRASH_ADDR_HIGH_MAX
on x86_32, the first high crash kernel memory reservation will fail, then
go into the "retry" loop and never came out as below.
-> reserve_crashkernel_generic() and high is true
-> alloc at [CRASH_ADDR_LOW_MAX, CRASH_ADDR_HIGH_MAX] fail
-> alloc at [0, CRASH_ADDR_LOW_MAX] fail and repeatedly
(because CRASH_ADDR_LOW_MAX = CRASH_ADDR_HIGH_MAX).
Fix it by change the out check condition.
After this patch, it print:
cannot allocate crashkernel (size:0x40000000)
Fixes: 9c08a2a139fe ("x86: kdump: use generic interface to simplify crashkernel reservation code")
Signed-off-by: Jinjie Ruan <ruanjinjie@xxxxxxxxxx>
---
v2:
- Peel off the other two patches.
- Update the commit message and fix tag.
---
kernel/crash_reserve.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/crash_reserve.c b/kernel/crash_reserve.c
index 5b2722a93a48..5073ae205f79 100644
--- a/kernel/crash_reserve.c
+++ b/kernel/crash_reserve.c
@@ -421,7 +421,7 @@ void __init reserve_crashkernel_generic(char *cmdline,
* For crashkernel=size[KMG],high, if the first attempt was
* for high memory, fall back to low memory.
*/
- if (high && search_end == CRASH_ADDR_HIGH_MAX) {
+ if (high && search_base == CRASH_ADDR_LOW_MAX) {
search_end = CRASH_ADDR_LOW_MAX;
search_base = 0;
goto retry;
--
2.34.1
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