Christophe Leroy 82efee6a87 powerpc/kprobes: Ignore traps that happened in real mode ... commit 21f8b2fa3c upstream. When a program check exception happens while MMU translation is disabled, following Oops happens in kprobe_handler() in the following code: } else if (*addr != BREAKPOINT_INSTRUCTION) { BUG: Unable to handle kernel data access on read at 0x0000e268 Faulting instruction address: 0xc000ec34 Oops: Kernel access of bad area, sig: 11 [#1] BE PAGE_SIZE=16K PREEMPT CMPC885 Modules linked in: CPU: 0 PID: 429 Comm: cat Not tainted 5.6.0-rc1-s3k-dev-00824-g84195dc6c58a #3267 NIP: c000ec34 LR: c000ecd8 CTR: c019cab8 REGS: ca4d3b58 TRAP: 0300 Not tainted (5.6.0-rc1-s3k-dev-00824-g84195dc6c58a) MSR: 00001032 <ME,IR,DR,RI> CR: 2a4d3c52 XER: 00000000 DAR: 0000e268 DSISR: c0000000 GPR00: c000b09c ca4d3c10 c66d0620 00000000 ca4d3c60 00000000 00009032 00000000 GPR08: 00020000 00000000 c087de44 c000afe0 c66d0ad0 100d3dd6 fffffff3 00000000 GPR16: 00000000 00000041 00000000 ca4d3d70 00000000 00000000 0000416d 00000000 GPR24: 00000004 c53b6128 00000000 0000e268 00000000 c07c0000 c07bb6fc ca4d3c60 NIP [c000ec34] kprobe_handler+0x128/0x290 LR [c000ecd8] kprobe_handler+0x1cc/0x290 Call Trace: [ca4d3c30] [c000b09c] program_check_exception+0xbc/0x6fc [ca4d3c50] [c000e43c] ret_from_except_full+0x0/0x4 --- interrupt: 700 at 0xe268 Instruction dump: 913e0008 81220000 38600001 3929ffff 91220000 80010024 bb410008 7c0803a6 38210020 4e800020 38600000 4e800020 <813b0000> 6d2a7fe0 2f8a0008 419e0154 ---[ end trace 5b9152d4cdadd06d ]--- kprobe is not prepared to handle events in real mode and functions running in real mode should have been blacklisted, so kprobe_handler() can safely bail out telling 'this trap is not mine' for any trap that happened while in real-mode. If the trap happened with MSR_IR or MSR_DR cleared, return 0 immediately. Reported-by: Larry Finger <Larry.Finger@lwfinger.net> Fixes: 6cc89bad60 ("powerpc/kprobes: Invoke handlers directly") Cc: stable@vger.kernel.org # v4.10+ Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/424331e2006e7291a1bfe40e7f3fa58825f565e1.1582054578.git.christophe.leroy@c-s.fr Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2020-04-17 10:48:53 +02:00
..
boot	powerpc/44x: Adjust indentation in ibm4xx_denali_fixup_memsize	2020-02-11 04:34:12 -08:00
configs	powerpc/mm/radix: Make Radix require HUGETLB_PAGE	2019-05-02 09:58:55 +02:00
crypto	powerpc updates for 4.19	2018-08-17 11:32:50 -07:00
include	powerpc/hash64/devmap: Use H_PAGE_THP_HUGE when setting up huge devmap PTE entries	2020-04-17 10:48:53 +02:00
kernel	powerpc/kprobes: Ignore traps that happened in real mode	2020-04-17 10:48:53 +02:00
kvm	KVM: PPC: Book3S PR: Free shared page if mmu initialization fails	2020-02-11 04:34:11 -08:00
lib	powerpc/64: Fix memcmp reading past the end of src/dest	2019-04-03 06:26:29 +02:00
math-emu
mm	mm/memory_hotplug: shrink zones when offlining memory	2020-01-29 16:43:27 +01:00
net	powerpc/bpf: Fix tail call implementation	2019-12-05 09:19:39 +01:00
oprofile	treewide: kzalloc() -> kcalloc()	2018-06-12 16:19:22 -07:00
perf	powerpc/perf: Fix unit_sel/cache_sel checks	2019-12-05 09:20:41 +01:00
platforms	powerpc/pseries: Avoid NULL pointer dereference when drmem is unavailable	2020-04-17 10:48:51 +02:00
purgatory	powerpc updates for 4.19	2018-08-17 11:32:50 -07:00
sysdev	powerpc/xive: Use XIVE_BAD_IRQ instead of zero to catch non configured IPIs	2020-04-17 10:48:53 +02:00
tools	powerpc/tools: Don't quote $objdump in scripts	2020-01-04 19:12:42 +01:00
xmon	powerpc/xmon: don't access ASDR in VMs	2020-02-11 04:33:58 -08:00
Kconfig	of: Add OF_DMA_DEFAULT_COHERENT & select it on powerpc	2020-02-11 04:34:03 -08:00
Kconfig.debug	Kconfig: consolidate the "Kernel hacking" menu	2018-08-02 08:06:48 +09:00
Makefile	powerpc: vdso: Make vdso32 installation conditional in vdso_install	2020-01-27 14:50:40 +01:00
Makefile.postlink