From 62772c8a24f7f5dc03a69dcdfae9d780462ba89c Mon Sep 17 00:00:00 2001
From: Masamichi Takagi <masamichi.takagi@riken.jp>
Date: Tue, 29 Jan 2019 13:40:37 +0900
Subject: [PATCH] gencore: Allocate ELF header to heap instead of stack

coredump() proceeds as follows:

1. coredump() calls gencore()
2. gencore() allocates ELF header to stack
3. gencore() prepares the core table and record the address of the ELF
   header to the table and return to coredump()
4. coredump() offloads __NR_coredump with the address of the core
   table

This fix prevents the ELF header from getting destroyed in the 3rd
step.

Change-Id: I770418c1658a6fdb640bb491fc076a31dfd41c22
Fujitsu: POSTK_TEMP_FIX_39
---
 kernel/gencore.c | 17 -----------------
 1 file changed, 17 deletions(-)

diff --git a/kernel/gencore.c b/kernel/gencore.c
index 410dfee9..3e747db6 100644
--- a/kernel/gencore.c
+++ b/kernel/gencore.c
@@ -228,11 +228,7 @@ int gencore(struct thread *thread, void *regs,
 	    struct coretable **coretable, int *chunks)
 {
 	struct coretable *ct = NULL;
-#ifdef POSTK_DEBUG_TEMP_FIX_39
 	Elf64_Ehdr *eh = NULL;
-#else
-	Elf64_Ehdr eh;
-#endif /*POSTK_DEBUG_TEMP_FIX_39*/
 	Elf64_Phdr *ph = NULL;
 	void *note = NULL;
 	struct vm_range *range, *next;
@@ -304,7 +300,6 @@ int gencore(struct thread *thread, void *regs,
 
 	dkprintf("now generate a core file image\n");
 
-#ifdef POSTK_DEBUG_TEMP_FIX_39
 	eh = kmalloc(sizeof(*eh), IHK_MC_AP_NOWAIT);
 	if (eh == NULL) {
 		dkprintf("could not alloc a elf header table.\n");
@@ -314,10 +309,6 @@ int gencore(struct thread *thread, void *regs,
 
 	offset += sizeof(*eh);
 	fill_elf_header(eh, segs);
-#else
-	offset += sizeof(eh);
-	fill_elf_header(&eh, segs);
-#endif /* POSTK_DEBUG_TEMP_FIX_39 */
 
 	/* program header table */
 	phsize = sizeof(Elf64_Phdr) * segs;
@@ -391,15 +382,9 @@ int gencore(struct thread *thread, void *regs,
 	}
 	memset(ct, 0, sizeof(*ct));
 
-#ifdef POSTK_DEBUG_TEMP_FIX_39
 	ct[0].addr = virt_to_phys(eh);	/* ELF header */
 	ct[0].len = 64;
 	dkprintf("coretable[0]: %lx@%lx(%lx)\n", ct[0].len, ct[0].addr, eh);
-#else
-	ct[0].addr = virt_to_phys(&eh);	/* ELF header */
-	ct[0].len = 64;
-	dkprintf("coretable[0]: %lx@%lx(%lx)\n", ct[0].len, ct[0].addr, &eh);
-#endif /* POSTK_DEBUG_TEMP_FIX_39 */
 
 	ct[1].addr = virt_to_phys(ph);	/* program header table */
 	ct[1].len = phsize;
@@ -511,8 +496,6 @@ void freecore(struct coretable **coretable)
 
 	kfree(phys_to_virt(ct[2].addr));	/* NOTE segment */
 	kfree(phys_to_virt(ct[1].addr));	/* ph */
-#ifdef POSTK_DEBUG_TEMP_FIX_39
 	kfree(phys_to_virt(ct[0].addr));	/* eh */
-#endif /*POSTK_DEBUG_TEMP_FIX_39*/
 	kfree(*coretable);
 }