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| author | Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> | 2018-05-09 13:42:20 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-05-13 20:50:06 +0300 |
| commit | a466ef76b815b86748d9870ef2a430af7b39c710 (patch) | |
| tree | 04a737c6be5691494571ee2fa66a65627ee77a93 /arch/x86/kernel/machine_kexec_32.c | |
| parent | ccda3c4b77777f66aeb3c531352bb40d59501c59 (diff) | |
| download | linux-a466ef76b815b86748d9870ef2a430af7b39c710.tar.xz | |
x86/kexec: Avoid double free_page() upon do_kexec_load() failure
>From ff82bedd3e12f0d3353282054ae48c3bd8c72012 Mon Sep 17 00:00:00 2001
From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Date: Wed, 9 May 2018 12:12:39 +0900
Subject: [PATCH v3] x86/kexec: avoid double free_page() upon do_kexec_load() failure.
syzbot is reporting crashes after memory allocation failure inside
do_kexec_load() [1]. This is because free_transition_pgtable() is called
by both init_transition_pgtable() and machine_kexec_cleanup() when memory
allocation failed inside init_transition_pgtable().
Regarding 32bit code, machine_kexec_free_page_tables() is called by both
machine_kexec_alloc_page_tables() and machine_kexec_cleanup() when memory
allocation failed inside machine_kexec_alloc_page_tables().
Fix this by leaving the error handling to machine_kexec_cleanup()
(and optionally setting NULL after free_page()).
[1] https://syzkaller.appspot.com/bug?id=91e52396168cf2bdd572fe1e1bc0bc645c1c6b40
Fixes: f5deb79679af6eb4 ("x86: kexec: Use one page table in x86_64 machine_kexec")
Fixes: 92be3d6bdf2cb349 ("kexec/i386: allocate page table pages dynamically")
Reported-by: syzbot <syzbot+d96f60296ef613fe1d69@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: thomas.lendacky@amd.com
Cc: prudo@linux.vnet.ibm.com
Cc: Huang Ying <ying.huang@intel.com>
Cc: syzkaller-bugs@googlegroups.com
Cc: takahiro.akashi@linaro.org
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: akpm@linux-foundation.org
Cc: dyoung@redhat.com
Cc: kirill.shutemov@linux.intel.com
Link: https://lkml.kernel.org/r/201805091942.DGG12448.tMFVFSJFQOOLHO@I-love.SAKURA.ne.jp
Diffstat (limited to 'arch/x86/kernel/machine_kexec_32.c')
| -rw-r--r-- | arch/x86/kernel/machine_kexec_32.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/arch/x86/kernel/machine_kexec_32.c b/arch/x86/kernel/machine_kexec_32.c index 60cdec6628b0..d1ab07ec8c9a 100644 --- a/arch/x86/kernel/machine_kexec_32.c +++ b/arch/x86/kernel/machine_kexec_32.c @@ -57,12 +57,17 @@ static void load_segments(void) static void machine_kexec_free_page_tables(struct kimage *image) { free_page((unsigned long)image->arch.pgd); + image->arch.pgd = NULL; #ifdef CONFIG_X86_PAE free_page((unsigned long)image->arch.pmd0); + image->arch.pmd0 = NULL; free_page((unsigned long)image->arch.pmd1); + image->arch.pmd1 = NULL; #endif free_page((unsigned long)image->arch.pte0); + image->arch.pte0 = NULL; free_page((unsigned long)image->arch.pte1); + image->arch.pte1 = NULL; } static int machine_kexec_alloc_page_tables(struct kimage *image) @@ -79,7 +84,6 @@ static int machine_kexec_alloc_page_tables(struct kimage *image) !image->arch.pmd0 || !image->arch.pmd1 || #endif !image->arch.pte0 || !image->arch.pte1) { - machine_kexec_free_page_tables(image); return -ENOMEM; } return 0; |