Revision 7ba1b689038726d34e3244c1ac9e2e18c2ea4787 authored by Ralf Baechle on 09 February 2017, 13:12:11 UTC, committed by David S. Miller on 10 February 2017, 18:41:13 UTC
If a USB-to-serial adapter is unplugged, the driver re-initializes, with
dev->hard_header_len and dev->addr_len set to zero, instead of the correct
values.  If then a packet is sent through the half-dead interface, the
kernel will panic due to running out of headroom in the skb when pushing
for the AX.25 headers resulting in this panic:

[<c0595468>] (skb_panic) from [<c0401f70>] (skb_push+0x4c/0x50)
[<c0401f70>] (skb_push) from [<bf0bdad4>] (ax25_hard_header+0x34/0xf4 [ax25])
[<bf0bdad4>] (ax25_hard_header [ax25]) from [<bf0d05d4>] (ax_header+0x38/0x40 [mkiss])
[<bf0d05d4>] (ax_header [mkiss]) from [<c041b584>] (neigh_compat_output+0x8c/0xd8)
[<c041b584>] (neigh_compat_output) from [<c043e7a8>] (ip_finish_output+0x2a0/0x914)
[<c043e7a8>] (ip_finish_output) from [<c043f948>] (ip_output+0xd8/0xf0)
[<c043f948>] (ip_output) from [<c043f04c>] (ip_local_out_sk+0x44/0x48)

This patch makes mkiss behave like the 6pack driver. 6pack does not
panic.  In 6pack.c sp_setup() (same function name here) the values for
dev->hard_header_len and dev->addr_len are set to the same values as in
my mkiss patch.

[ralf@linux-mips.org: Massages original submission to conform to the usual
standards for patch submissions.]

Signed-off-by: Thomas Osterried <thomas@osterried.de>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent b85ea00
Raw File
initramfs_data.S
/*
  initramfs_data includes the compressed binary that is the
  filesystem used for early user space.
  Note: Older versions of "as" (prior to binutils 2.11.90.0.23
  released on 2001-07-14) dit not support .incbin.
  If you are forced to use older binutils than that then the
  following trick can be applied to create the resulting binary:


  ld -m elf_i386  --format binary --oformat elf32-i386 -r \
  -T initramfs_data.scr initramfs_data.cpio.gz -o initramfs_data.o
   ld -m elf_i386  -r -o built-in.o initramfs_data.o

  For including the .init.ramfs sections, see include/asm-generic/vmlinux.lds.

  The above example is for i386 - the parameters vary from architectures.
  Eventually look up LDFLAGS_BLOB in an older version of the
  arch/$(ARCH)/Makefile to see the flags used before .incbin was introduced.

  Using .incbin has the advantage over ld that the correct flags are set
  in the ELF header, as required by certain architectures.
*/

#include <linux/stringify.h>
#include <asm-generic/vmlinux.lds.h>

.section .init.ramfs,"a"
__irf_start:
.incbin __stringify(INITRAMFS_IMAGE)
__irf_end:
.section .init.ramfs.info,"a"
.globl VMLINUX_SYMBOL(__initramfs_size)
VMLINUX_SYMBOL(__initramfs_size):
#ifdef CONFIG_64BIT
	.quad __irf_end - __irf_start
#else
	.long __irf_end - __irf_start
#endif
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