korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-11-28 22:54:05 +08:00
Code Issues Packages Projects Releases Wiki Activity
be97d0db5f
linux/arch
History
Deepak Gupta be97d0db5f
riscv: VMAP_STACK overflow detection thread-safe 
commit 31da94c25a ("riscv: add VMAP_STACK overflow detection") added
support for CONFIG_VMAP_STACK. If overflow is detected, CPU switches to
`shadow_stack` temporarily before switching finally to per-cpu
`overflow_stack`.

If two CPUs/harts are racing and end up in over flowing kernel stack, one
or both will end up corrupting each other state because `shadow_stack` is
not per-cpu. This patch optimizes per-cpu overflow stack switch by
directly picking per-cpu `overflow_stack` and gets rid of `shadow_stack`.

Following are the changes in this patch

 - Defines an asm macro to obtain per-cpu symbols in destination
   register.
 - In entry.S, when overflow is detected, per-cpu overflow stack is
   located using per-cpu asm macro. Computing per-cpu symbol requires
   a temporary register. x31 is saved away into CSR_SCRATCH
   (CSR_SCRATCH is anyways zero since we're in kernel).

Please see Links for additional relevant disccussion and alternative
solution.

Tested by `echo EXHAUST_STACK > /sys/kernel/debug/provoke-crash/DIRECT`
Kernel crash log below

 Insufficient stack space to handle exception!/debug/provoke-crash/DIRECT
 Task stack:     [0xff20000010a98000..0xff20000010a9c000]
 Overflow stack: [0xff600001f7d98370..0xff600001f7d99370]
 CPU: 1 PID: 205 Comm: bash Not tainted 6.1.0-rc2-00001-g328a1f96f7b9 #34
 Hardware name: riscv-virtio,qemu (DT)
 epc : __memset+0x60/0xfc
  ra : recursive_loop+0x48/0xc6 [lkdtm]
 epc : ffffffff808de0e4 ra : ffffffff0163a752 sp : ff20000010a97e80
  gp : ffffffff815c0330 tp : ff600000820ea280 t0 : ff20000010a97e88
  t1 : 000000000000002e t2 : 3233206874706564 s0 : ff20000010a982b0
  s1 : 0000000000000012 a0 : ff20000010a97e88 a1 : 0000000000000000
  a2 : 0000000000000400 a3 : ff20000010a98288 a4 : 0000000000000000
  a5 : 0000000000000000 a6 : fffffffffffe43f0 a7 : 00007fffffffffff
  s2 : ff20000010a97e88 s3 : ffffffff01644680 s4 : ff20000010a9be90
  s5 : ff600000842ba6c0 s6 : 00aaaaaac29e42b0 s7 : 00fffffff0aa3684
  s8 : 00aaaaaac2978040 s9 : 0000000000000065 s10: 00ffffff8a7cad10
  s11: 00ffffff8a76a4e0 t3 : ffffffff815dbaf4 t4 : ffffffff815dbaf4
  t5 : ffffffff815dbab8 t6 : ff20000010a9bb48
 status: 0000000200000120 badaddr: ff20000010a97e88 cause: 000000000000000f
 Kernel panic - not syncing: Kernel stack overflow
 CPU: 1 PID: 205 Comm: bash Not tainted 6.1.0-rc2-00001-g328a1f96f7b9 #34
 Hardware name: riscv-virtio,qemu (DT)
 Call Trace:
 [<ffffffff80006754>] dump_backtrace+0x30/0x38
 [<ffffffff808de798>] show_stack+0x40/0x4c
 [<ffffffff808ea2a8>] dump_stack_lvl+0x44/0x5c
 [<ffffffff808ea2d8>] dump_stack+0x18/0x20
 [<ffffffff808dec06>] panic+0x126/0x2fe
 [<ffffffff800065ea>] walk_stackframe+0x0/0xf0
 [<ffffffff0163a752>] recursive_loop+0x48/0xc6 [lkdtm]
 SMP: stopping secondary CPUs
 ---[ end Kernel panic - not syncing: Kernel stack overflow ]---

Cc: Guo Ren <guoren@kernel.org>
Cc: Jisheng Zhang <jszhang@kernel.org>
Link: https://lore.kernel.org/linux-riscv/Y347B0x4VUNOd6V7@xhacker/T/#t
Link: https://lore.kernel.org/lkml/20221124094845.1907443-1-debug@rivosinc.com/
Signed-off-by: Deepak Gupta <debug@rivosinc.com>
Co-developed-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Acked-by: Guo Ren <guoren@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20230927224757.1154247-9-samitolvanen@google.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-10-27 14:43:05 -07:00
..
alpha Kbuild updates for v6.6 2023-09-05 11:01:47 -07:00
arc ARC updates for v6.6 2023-09-04 15:38:24 -07:00
arm ARM: 2023-09-07 13:52:20 -07:00
arm64 RISC-V Patches for the 6.6 Merge Window, Part 2 (try 2) 2023-09-09 14:25:11 -07:00
csky arch/csky 2nd patches for 6.6 2023-09-01 08:02:45 -07:00
hexagon Add x86 shadow stack support 2023-08-31 12:20:12 -07:00
ia64 Kbuild updates for v6.6 2023-09-05 11:01:47 -07:00
loongarch LoongArch changes for v6.6 2023-09-08 12:16:52 -07:00
m68k ata changes for 6.6 2023-09-05 12:37:28 -07:00
microblaze Microblaze patches for 6.6-rc1 2023-09-05 10:15:22 -07:00
mips ARM: 2023-09-07 13:52:20 -07:00
nios2 Add x86 shadow stack support 2023-08-31 12:20:12 -07:00
openrisc OpenRISC updates for 6.6 2023-09-05 10:09:31 -07:00
parisc ata changes for 6.6 2023-09-05 12:37:28 -07:00
powerpc ata changes for 6.6 2023-09-05 12:37:28 -07:00
riscv riscv: VMAP_STACK overflow detection thread-safe 2023-10-27 14:43:05 -07:00
s390 Including fixes from netfilter and bpf. 2023-09-07 18:33:07 -07:00
sh sh updates for v6.6 2023-09-09 14:46:57 -07:00
sparc ata changes for 6.6 2023-09-05 12:37:28 -07:00
um This pull request contains the following changes for UML: 2023-09-04 11:32:21 -07:00
x86 Fix preemption delays in the SGX code, remove unnecessarily UAPI-exported code, 2023-09-10 10:39:31 -07:00
xtensa Xtensa updates for v6.6 2023-09-07 10:30:17 -07:00
.gitignore
Kconfig Add x86 shadow stack support 2023-08-31 12:20:12 -07:00