[PATCH v2 4/6] powerpc/kdump: preserve user-specified memory limit

Sourabh Jain
2025-01-21T11:55:20Z

Commit 59d58189f3d9 ("crash: fix crash memory reserve exceed system
memory bug") fails crashkernel parsing if the crash size is found to be
higher than system RAM, which makes the memory_limit adjustment code
ineffective due to an early exit from reserve_crashkernel().

Regardless lets not violated the user-specified memory limit by
adjusting it. Remove this adjustment to ensure all reservations stay
within the limit. Commit f94f5ac07983 ("powerpc/fadump: Don't update
the user-specified memory limit") did the same for fadump.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Baoquan he <bhe@redhat.com>
Cc: Hari Bathini <hbathini@linux.ibm.com>
CC: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: kexec@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
---
arch/powerpc/kexec/core.c | 8 --------
1 file changed, 8 deletions(-)

diff --git a/arch/powerpc/kexec/core.c b/arch/powerpc/kexec/core.c
index b8333a49ea5d..4945b33322ae 100644
--- a/arch/powerpc/kexec/core.c
+++ b/arch/powerpc/kexec/core.c
@@ -150,14 +150,6 @@ void __init reserve_crashkernel(void)
return;
}

- /* Crash kernel trumps memory limit */
- if (memory_limit && memory_limit <= crashk_res.end) {
- memory_limit = crashk_res.end + 1;
- total_mem_sz = memory_limit;
- printk("Adjusted memory limit for crashkernel, now 0x%llx\n",
- memory_limit);
- }
-
printk(KERN_INFO "Reserving %ldMB of memory at %ldMB "
"for crashkernel (System RAM: %ldMB)\n",
(unsigned long)(crash_size >> 20),
--
2.47.1