Christophe Leroy 3978eb7851 powerpc/32: Add early stack overflow detection with VMAP stack. ... To avoid recursive faults, stack overflow detection has to be performed before writing in the stack in exception prologs. Do it by checking the alignment. If the stack pointer alignment is wrong, it means it is pointing to the following or preceding page. Without VMAP stack, a stack overflow is catastrophic. With VMAP stack, a stack overflow isn't destructive, so don't panic. Kill the task with SIGSEGV instead. A dedicated overflow stack is set up for each CPU. lkdtm: Performing direct entry EXHAUST_STACK lkdtm: Calling function with 512 frame size to depth 32 ... lkdtm: loop 32/32 ... lkdtm: loop 31/32 ... lkdtm: loop 30/32 ... lkdtm: loop 29/32 ... lkdtm: loop 28/32 ... lkdtm: loop 27/32 ... lkdtm: loop 26/32 ... lkdtm: loop 25/32 ... lkdtm: loop 24/32 ... lkdtm: loop 23/32 ... lkdtm: loop 22/32 ... lkdtm: loop 21/32 ... lkdtm: loop 20/32 ... Kernel stack overflow in process test[359], r1=c900c008 Oops: Kernel stack overflow, sig: 6 [#1] BE PAGE_SIZE=4K MMU=Hash PowerMac Modules linked in: CPU: 0 PID: 359 Comm: test Not tainted 5.3.0-rc7+ #2225 NIP: c0622060 LR: c0626710 CTR: 00000000 REGS: c0895f48 TRAP: 0000 Not tainted (5.3.0-rc7+) MSR: 00001032 <ME,IR,DR,RI> CR: 28004224 XER: 00000000 GPR00: c0626ca4 c900c008 c783c000 c07335cc c900c010 c07335cc c900c0f0 c07335cc GPR08: c900c0f0 00000001 00000000 00000000 28008222 00000000 00000000 00000000 GPR16: 00000000 00000000 10010128 10010000 b799c245 10010158 c07335cc 00000025 GPR24: c0690000 c08b91d4 c068f688 00000020 c900c0f0 c068f668 c08b95b4 c08b91d4 NIP [c0622060] format_decode+0x0/0x4d4 LR [c0626710] vsnprintf+0x80/0x5fc Call Trace: [c900c068] [c0626ca4] vscnprintf+0x18/0x48 [c900c078] [c007b944] vprintk_store+0x40/0x214 [c900c0b8] [c007bf50] vprintk_emit+0x90/0x1dc [c900c0e8] [c007c5cc] printk+0x50/0x60 [c900c128] [c03da5b0] recursive_loop+0x44/0x6c [c900c338] [c03da5c4] recursive_loop+0x58/0x6c [c900c548] [c03da5c4] recursive_loop+0x58/0x6c [c900c758] [c03da5c4] recursive_loop+0x58/0x6c [c900c968] [c03da5c4] recursive_loop+0x58/0x6c [c900cb78] [c03da5c4] recursive_loop+0x58/0x6c [c900cd88] [c03da5c4] recursive_loop+0x58/0x6c [c900cf98] [c03da5c4] recursive_loop+0x58/0x6c [c900d1a8] [c03da5c4] recursive_loop+0x58/0x6c [c900d3b8] [c03da5c4] recursive_loop+0x58/0x6c [c900d5c8] [c03da5c4] recursive_loop+0x58/0x6c [c900d7d8] [c03da5c4] recursive_loop+0x58/0x6c [c900d9e8] [c03da5c4] recursive_loop+0x58/0x6c [c900dbf8] [c03da5c4] recursive_loop+0x58/0x6c [c900de08] [c03da67c] lkdtm_EXHAUST_STACK+0x30/0x4c [c900de18] [c03da3e8] direct_entry+0xc8/0x140 [c900de48] [c029fb40] full_proxy_write+0x64/0xcc [c900de68] [c01500f8] __vfs_write+0x30/0x1d0 [c900dee8] [c0152cb8] vfs_write+0xb8/0x1d4 [c900df08] [c0152f7c] ksys_write+0x58/0xe8 [c900df38] [c0014208] ret_from_syscall+0x0/0x34 --- interrupt: c01 at 0xf806664 LR = 0x1000c868 Instruction dump: 4bffff91 80010014 7c832378 7c0803a6 38210010 4e800020 3d20c08a 3ca0c089 8089a0cc 38a58f0c 38600001 4ba2d494 <9421ffe0> 7c0802a6 bfc10018 7c9f2378 Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/1b89c121b4070c7ee99e4f22cc178f15a736b07b.1576916812.git.christophe.leroy@c-s.fr		2020-01-27 22:35:49 +11:00
..
alpha	alpha: use pgtable-nopud instead of 4level-fixup	2019-12-04 19:44:14 -08:00
arc	treewide: Use sizeof_field() macro	2019-12-09 10:36:44 -08:00
arm	KVM/arm fixes for .5.5, take #1	2019-12-18 17:47:38 +01:00
arm64	mm/memory_hotplug: shrink zones when offlining memory	2020-01-04 13:55:08 -08:00
c6x	c6x: use pgtable-nopud instead of 4level-fixup	2019-12-04 19:44:15 -08:00
csky	dma-mapping updates for 5.5-rc1	2019-11-28 11:16:43 -08:00
h8300	h8300: Move EXCEPTION_TABLE to RO_DATA segment	2019-11-04 18:12:55 +01:00
hexagon	hexagon: define ioremap_uc	2020-01-04 13:55:09 -08:00
ia64	mm/memory_hotplug: shrink zones when offlining memory	2020-01-04 13:55:08 -08:00
m68k	Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu	2019-12-05 12:20:42 -08:00
microblaze	microblaze: use pgtable-nopmd instead of 4level-fixup	2019-12-04 19:44:15 -08:00
mips	A collection of MIPS fixes:	2020-01-04 14:16:57 -08:00
nds32	nds32: use pgtable-nopmd instead of 4level-fixup	2019-12-04 19:44:15 -08:00
nios2	nios2: Fix ioremap	2019-12-12 16:34:33 +08:00
openrisc	OpenRISC updates for 5.5	2019-12-02 17:18:43 -08:00
parisc	parisc: Fix compiler warnings in debug_core.c	2019-12-20 21:01:42 +01:00
powerpc	powerpc/32: Add early stack overflow detection with VMAP stack.	2020-01-27 22:35:49 +11:00
riscv	riscv: prefix IRQ_ macro names with an RV_ namespace	2020-01-04 21:48:59 -08:00
s390	mm/memory_hotplug: shrink zones when offlining memory	2020-01-04 13:55:08 -08:00
sh	mm/memory_hotplug: shrink zones when offlining memory	2020-01-04 13:55:08 -08:00
sparc	treewide: Use sizeof_field() macro	2019-12-09 10:36:44 -08:00
um	um: add support for folded p4d page tables	2019-12-04 19:44:15 -08:00
unicore32	generic ioremap support	2019-11-28 10:57:12 -08:00
x86	mm/memory_hotplug: shrink zones when offlining memory	2020-01-04 13:55:08 -08:00
xtensa	arch: sembuf.h: make uapi asm/sembuf.h self-contained	2019-12-04 19:44:14 -08:00
.gitignore	…
Kconfig	arch/Kconfig: fix indentation	2019-12-04 19:44:12 -08:00