linux-kernel - [PATCH 3/5] powerpc/kdump: preserve user-specified memory limit

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Message-ID: <20241217064613.1042866-4-sourabhjain@linux.ibm.com>
Date: Tue, 17 Dec 2024 12:16:11 +0530
From: Sourabh Jain <sourabhjain@...ux.ibm.com>
To: linuxppc-dev@...ts.ozlabs.org
Cc: Sourabh Jain <sourabhjain@...ux.ibm.com>,
        Andrew Morton <akpm@...ux-foundation.org>, Baoquan he <bhe@...hat.com>,
        Hari Bathini <hbathini@...ux.ibm.com>,
        Madhavan Srinivasan <maddy@...ux.ibm.com>,
        Michael Ellerman <mpe@...erman.id.au>, kexec@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 3/5] powerpc/kdump: preserve user-specified memory limit

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@...ux-foundation.org>
Cc: Baoquan he <bhe@...hat.com>
Cc: Hari Bathini <hbathini@...ux.ibm.com>
CC: Madhavan Srinivasan <maddy@...ux.ibm.com>
Cc: Michael Ellerman <mpe@...erman.id.au>
Cc: kexec@...ts.infradead.org
Cc: linux-kernel@...r.kernel.org
Signed-off-by: Sourabh Jain <sourabhjain@...ux.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