linux-kernel - [PATCH] fs: heap/bss calculation ignore section above STACK

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Message-ID: <1437891661-32007-1-git-send-email-noamc@ezchip.com>
Date:	Sun, 26 Jul 2015 09:21:01 +0300
From:	Noam Camus <noamc@...hip.com>
To:	<linux-kernel@...r.kernel.org>, <linux-fsdevel@...r.kernel.org>,
	<viro@...iv.linux.org.uk>
CC:	<Alexey.Brodkin@...opsys.com>, <vgupta@...opsys.com>,
	<adilger@...ger.ca>, <giladb@...hip.com>,
	Noam Camus <noamc@...hip.com>
Subject: [PATCH] fs: heap/bss calculation ignore section above STACK_TOP.

From: Noam Camus <noamc@...hip.com>

Today bss/heap is placed above last loaded sections.
Current check is only against TASK_SIZE, maybe since most architectures do:

But this is not true for all of them and a gap between TASK_SIZE
and STACK_TOP is possible and may be used for variant purposes.
For example we use it for a special physical memory mapping.

In such case of section in this gap we skip it for matter of
heap/bss calculation.
set_brk will never work for such case anyway.

Signed-off-by: Noam Camus <noamc@...hip.com>
---
 fs/binfmt_elf.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 6b65996..e445886 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -962,6 +962,9 @@ static int load_elf_binary(struct linux_binprm *bprm)
 
 		k = elf_ppnt->p_vaddr + elf_ppnt->p_filesz;
 
+		if (k >= STACK_TOP)
+			continue;
+
 		if (k > elf_bss)
 			elf_bss = k;
 		if ((elf_ppnt->p_flags & PF_X) && end_code < k)
-- 
1.7.1

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