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
..
boot	powerpc/devicetrees: Change 'gpios' to 'cs-gpios' on fsl, spi nodes	2020-01-23 21:31:14 +11:00
configs	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace	2019-12-01 13:26:18 -08:00
crypto	powerpc updates for 5.5	2019-11-30 14:35:43 -08:00
include	powerpc: align stack to 2 * THREAD_SIZE with VMAP_STACK	2020-01-26 22:15:09 +11:00
kernel	powerpc/32: Add early stack overflow detection with VMAP stack.	2020-01-27 22:35:49 +11:00
kexec	powerpc: Avoid clang warnings around setjmp and longjmp	2019-11-25 21:45:43 +11:00
kvm	powerpc/mm: Remove kvm radix prefetch workaround for Power9 DD2.2	2020-01-26 00:11:37 +11:00
lib	powerpc: Fix __clear_user() with KUAP enabled	2019-12-16 23:19:44 +11:00
math-emu	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152	2019-05-30 11:26:32 -07:00
mm	powerpc/mm: Remove kvm radix prefetch workaround for Power9 DD2.2	2020-01-26 00:11:37 +11:00
net	treewide: Use sizeof_field() macro	2019-12-09 10:36:44 -08:00
oprofile	powerpc: use probe_user_read() and probe_user_write()	2020-01-26 00:11:35 +11:00
perf	powerpc: use probe_user_read() and probe_user_write()	2020-01-26 00:11:35 +11:00
platforms	powerpc/pseries/lparcfg: Fix display of Maximum Memory	2020-01-26 00:11:37 +11:00
purgatory	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441	2019-06-05 17:37:17 +02:00
sysdev	powerpc: use probe_user_read() and probe_user_write()	2020-01-26 00:11:35 +11:00
tools	powerpc/tools: Don't quote $objdump in scripts	2019-10-30 22:55:12 +11:00
xmon	powerpc/xmon: Fix compile error in print_insn* functions	2020-01-26 00:11:35 +11:00
Kbuild	powerpc/kexec: Move kexec files into a dedicated subdir.	2019-11-21 15:41:34 +11:00
Kconfig	powerpc: Remove STRICT_KERNEL_RWX incompatibility with RELOCATABLE	2020-01-16 14:59:36 +10:00
Kconfig.debug	powerpc/ptdump: Only enable PPC_CHECK_WX with STRICT_KERNEL_RWX	2020-01-23 21:31:13 +11:00
Makefile	powerpc: Don't add -mabi= flags when building with Clang	2019-11-25 21:45:43 +11:00
Makefile.postlink	kbuild: add $(BASH) to run scripts with bash-extension	2019-09-04 22:54:13 +09:00