It's reasonable. Ack.
Acked-by: Baoquan He
On 08/24/16 at 09:05pm, Thiago Jung Bauermann wrote:
> If kexec_apply_relocations fails, kexec_load_purgatory frees pi->sechdrs
> and pi->purgatory_buf. This is redundant, because in case of error
> kimage_file_prepare_segments calls kimage_file_post_load_cleanup,
> which will also free those buffers.
>
> This causes two warnings like the following, one for pi->sechdrs and the
> other for pi->purgatory_buf:
>
> [ 18.112843] kexec-bzImage64: Loading purgatory failed
> [ 18.113257] [ cut here ]
> [ 18.113263] WARNING: CPU: 1 PID: 2119 at mm/vmalloc.c:1490
> __vunmap+0xc1/0xd0
> [ 18.113264] Trying to vfree() nonexistent vm area (c9e91000)
> [ 18.113367] Modules linked in:
> [ 18.113371] CPU: 1 PID: 2119 Comm: kexec Not tainted 4.8.0-rc3+ #5
> [ 18.113372] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
> Bochs 01/01/2011
> [ 18.113373] 88003bbb7dc8 8132eca8
> 88003bbb7e18
> [ 18.113376] 88003bbb7e08 8105f1bb
> 05d281175bf8
> [ 18.113377] c9e91000 0001
> 88003e5f8c00
> [ 18.113379] Call Trace:
> [ 18.113384] [] dump_stack+0x4d/0x65
> [ 18.113386] [] __warn+0xcb/0xf0
> [ 18.113388] [] warn_slowpath_fmt+0x4f/0x60
> [ 18.113390] [] ? find_vmap_area+0x19/0x70
> [ 18.113393] [] ? kimage_file_post_load_cleanup+0x47/0xb0
> [ 18.113394] [] __vunmap+0xc1/0xd0
> [ 18.113396] [] vfree+0x2e/0x70
> [ 18.113397] [] kimage_file_post_load_cleanup+0x5e/0xb0
> [ 18.113398] [] SyS_kexec_file_load+0x448/0x680
> [ 18.113401] [] ? putname+0x54/0x60
> [ 18.113403] [] ? do_sys_open+0x190/0x1f0
> [ 18.113407] [] entry_SYSCALL_64_fastpath+0x13/0x8f
> [ 18.113408] ---[ end trace 158bb74f5950ca2b ]---
>
> Fix by setting pi->sechdrs an pi->purgatory_buf to NULL, since vfree
> won't try to free a NULL pointer.
>
> Signed-off-by: Thiago Jung Bauermann
> ---
> kernel/kexec_file.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
> index 503bc2d348e5..037c321c5618 100644
> --- a/kernel/kexec_file.c
> +++ b/kernel/kexec_file.c
> @@ -887,7 +887,10 @@ int kexec_load_purgatory(struct kimage *image, unsigned
> long min,
> return 0;
> out:
> vfree(pi->sechdrs);
> + pi->sechdrs = NULL;
> +
> vfree(pi->purgatory_buf);
> + pi->purgatory_buf = NULL;
> return ret;
> }
>
> --
> 1.9.1
>
>
> ___
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