[PATCH 0/2] arm: Replace this_cpu_* with raw_cpu_* in panic_bad_stack()

[Zhen Lei]

I'm analyzing a strange problem these days, and I find that there are some areas in
panic_bad_stack() that can be optimized. That is, replace this_cpu_* with raw_cpu_* .

Just optimization, it is unlikely to cause the following exception nesting, because of
"lr : __bad_stack+0x88/0x8c".

[20220819163739]Unable to handle kernel paging request at virtual address f7ffff94901b8048
[20220819163739]Mem abort info:
[20220819163739]  ESR = 0x96000004
[20220819163739]  EC = 0x25: DABT (current EL), IL = 32 bits
[20220819163739]  SET = 0, FnV = 0
[20220819163739]  EA = 0, S1PTW = 0
[20220819163739]Data abort info:
[20220819163739]  ISV = 0, ISS = 0x00000004
[20220819163739]  CM = 0, WnR = 0
[20220819163739][f7ffff94901b8048] address between user and kernel address ranges
[20220819163739]Internal error: Oops: 96000004 [#1] PREEMPT SMP
[20220819163739]Modules linked in: ...
[20220819163740]CPU: 2 PID: 1272 Comm: 00002SWDLMain Tainted: G        W  O      5.10.0 #1
[20220819163740]Hardware name: hisilicon,hi1213-fpga (DT)
[20220819163740]pstate: 000003c5 (nzcv DAIF -PAN -UAO -TCO BTYPE=--)
[20220819163740]pc : __bad_stack+0x4c/0x8c
[20220819163740]lr : __bad_stack+0x88/0x8c
[20220819163740]sp : ffffff953ffa8160
[20220819163740]x29: f7ffff953ffa8120 x28: f7ffff94901b8040 
[20220819163740]x27: ffffffeb72ea6940 x26: ffffffebeee6cf10 
[20220819163740]x25: ffffffebef627000 x24: 0000000000000000 
[20220819163740]x23: 00000000600003c5 x22: f7ffffebeee11904 
[20220819163740]x21: ffffff953ffa82b0 x20: 0000007fffffffff 
[20220819163740]x19: f7ffffc0133ab898 x18: 0000000000000000 
[20220819163740]x17: 0000000000000000 x16: ffffffebef32f0a0 
[20220819163740]x15: 00000000624057a0 x14: 953325a7da350fb3 
[20220819163740]x13: 09bbbe32ce2b3c11 x12: c15a0e2d1991997b 
[20220819163740]x11: 0bc8be839e7850d0 x10: cafa1cb223203045 
[20220819163740]x9 : f36bed299e5840dc x8 : ffffffc0133aba48 
[20220819163740]x7 : ffffff953b1b0480 x6 : ffffffebef3e1000 
[20220819163740]x5 : 0000000000000000 x4 : 0000000000000001 
[20220819163740]x3 : f7ffffc0133ab750 x2 : 0000000000000025 
[20220819163740]x1 : 0000000096000004 x0 : ffffff953ffa8160 
[20220819163740]Call trace:
[20220819163740] __bad_stack+0x4c/0x8c
[20220819163740]Code: a90d6ffa a90e77fc 910543f5 d538411c (f9400794) 
[20220819163740]---[ end trace 07532bfa2c24851c ]---
[20220819163740]Kernel panic - not syncing: Oops: Fatal exception


Zhen Lei (2):
  arm64/traps: Replace this_cpu_* with raw_cpu_* in panic_bad_stack()
  ARM: Replace this_cpu_* with raw_cpu_* in panic_bad_stack()

 arch/arm/kernel/traps.c   | 4 ++--
 arch/arm64/kernel/traps.c | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

-- 
2.25.1