linux/arch/m68k/kernel
Finn Thain b845b574f8 m68k: Move signal frame following exception on 68020/030
On 68030/020, an instruction such as, moveml %a2-%a3/%a5,%sp@- may cause
a stack page fault during instruction execution (i.e. not at an
instruction boundary) and produce a format 0xB exception frame.

In this situation, the value of USP will be unreliable.  If a signal is
to be delivered following the exception, this USP value is used to
calculate the location for a signal frame.  This can result in a
corrupted user stack.

The corruption was detected in dash (actually in glibc) where it showed
up as an intermittent "stack smashing detected" message and crash
following signal delivery for SIGCHLD.

It was hard to reproduce that failure because delivery of the signal
raced with the page fault and because the kernel places an unpredictable
gap of up to 7 bytes between the USP and the signal frame.

A format 0xB exception frame can be produced by a bus error or an
address error.  The 68030 Users Manual says that address errors occur
immediately upon detection during instruction prefetch.  The instruction
pipeline allows prefetch to overlap with other instructions, which means
an address error can arise during the execution of a different
instruction.  So it seems likely that this patch may help in the address
error case also.

Reported-and-tested-by: Stan Johnson <userm57@yahoo.com>
Link: https://lore.kernel.org/all/CAMuHMdW3yD22_ApemzW_6me3adq6A458u1_F0v-1EYwK_62jPA@mail.gmail.com/
Cc: Michael Schmitz <schmitzmic@gmail.com>
Cc: Andreas Schwab <schwab@linux-m68k.org>
Cc: stable@vger.kernel.org
Co-developed-by: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Finn Thain <fthain@linux-m68k.org>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/r/9e66262a754fcba50208aa424188896cc52a1dd1.1683365892.git.fthain@linux-m68k.org
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
2023-05-22 13:51:20 +02:00
..
syscalls arch: syscalls: simplify uapi/kapi directory creation 2022-03-31 12:03:46 +09:00
.gitignore .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
asm-offsets.c m68k: Remove set_fs() 2021-09-24 13:35:07 +02:00
bootinfo_proc.c proc: convert everything to "struct proc_ops" 2020-02-04 03:05:26 +00:00
dma.c m68k: dma: Remove unnecessary include of asm/cacheflush.h 2021-05-10 11:47:00 +02:00
early_printk.c m68knommu: remove obsolete 68360 support 2016-03-07 10:07:17 +10:00
entry.S m68k: Add kernel seccomp support 2023-01-30 16:40:15 +01:00
head.S m68k: Introduce a virtual m68k machine 2022-04-11 11:48:01 +02:00
ints.c m68k: Do not rely on magic indirect includes 2014-03-05 13:28:32 +01:00
irq.c Disintegrate asm/system.h for M68K 2012-03-28 18:30:02 +01:00
machine_kexec.c m68k: kexec: Include <linux/reboot.h> 2023-04-21 09:53:54 +02:00
Makefile kbuild: use obj-y instead extra-y for objects placed at the head 2022-10-02 18:04:05 +09:00
module.c m68k/kernel: Modernize printing of kernel messages 2017-02-12 10:36:52 +01:00
pcibios.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
process.c [elf][non-regset] uninline elf_core_copy_task_fpregs() (and lose pt_regs argument) 2022-11-24 23:24:23 -05:00
ptrace.c m68k: Add kernel seccomp support 2023-01-30 16:40:15 +01:00
relocate_kernel.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
setup_mm.c m68k: mm: Move initrd phys_to_virt handling after paging_init() 2023-03-06 14:09:42 +01:00
setup_no.c m68k: use strscpy() to instead of strncpy() 2022-12-05 09:07:21 +10:00
setup.c m68k: pull mach_beep in setup.c 2017-11-06 08:25:21 +10:00
signal.c m68k: Move signal frame following exception on 68020/030 2023-05-22 13:51:20 +02:00
sun3-head.S m68k/sun3: Remove is_medusa and m68k_pgtable_cachemode 2018-08-31 09:30:42 +02:00
sys_m68k.c arch/m68k/kernel/sys_m68k: use vma_lookup() in sys_cacheflush() 2021-06-29 10:53:51 -07:00
syscalltable.S m68k: syscalls: switch to generic syscalltbl.sh 2021-04-06 09:33:20 +02:00
time.c m68knommu: fix undefined reference to `mach_get_rtc_pll' 2022-05-25 00:03:58 +10:00
traps.c m68k: Only force 030 bus error if PC not in exception table 2023-03-06 14:09:42 +01:00
uboot.c mm: don't include asm/pgtable.h if linux/mm.h is already included 2020-06-09 09:39:13 -07:00
vectors.c Disintegrate asm/system.h for M68K 2012-03-28 18:30:02 +01:00
vmlinux-nommu.lds objtool/idle: Validate __cpuidle code as noinstr 2023-01-13 11:48:15 +01:00
vmlinux-std.lds objtool/idle: Validate __cpuidle code as noinstr 2023-01-13 11:48:15 +01:00
vmlinux-sun3.lds objtool/idle: Validate __cpuidle code as noinstr 2023-01-13 11:48:15 +01:00
vmlinux.lds.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00