[PATCH v2] powerpc/code-patching: Fix KASAN hit by not flagging text patching area as VM_ALLOC

[Madhavan Srinivasan]

On Wed, 12 Feb 2025 07:46:28 +0100, Christophe Leroy wrote:
> Erhard reported the following KASAN hit while booting his PowerMac G4
> with a KASAN-enabled kernel 6.13-rc6:
> 
>   BUG: KASAN: vmalloc-out-of-bounds in copy_to_kernel_nofault+0xd8/0x1c8
>   Write of size 8 at addr f1000000 by task chronyd/1293
> 
>   CPU: 0 UID: 123 PID: 1293 Comm: chronyd Tainted: G        W          6.13.0-rc6-PMacG4 #2
>   Tainted: [W]=WARN
>   Hardware name: PowerMac3,6 7455 0x80010303 PowerMac
>   Call Trace:
>   [c2437590] [c1631a84] dump_stack_lvl+0x70/0x8c (unreliable)
>   [c24375b0] [c0504998] print_report+0xdc/0x504
>   [c2437610] [c050475c] kasan_report+0xf8/0x108
>   [c2437690] [c0505a3c] kasan_check_range+0x24/0x18c
>   [c24376a0] [c03fb5e4] copy_to_kernel_nofault+0xd8/0x1c8
>   [c24376c0] [c004c014] patch_instructions+0x15c/0x16c
>   [c2437710] [c00731a8] bpf_arch_text_copy+0x60/0x7c
>   [c2437730] [c0281168] bpf_jit_binary_pack_finalize+0x50/0xac
>   [c2437750] [c0073cf4] bpf_int_jit_compile+0xb30/0xdec
>   [c2437880] [c0280394] bpf_prog_select_runtime+0x15c/0x478
>   [c24378d0] [c1263428] bpf_prepare_filter+0xbf8/0xc14
>   [c2437990] [c12677ec] bpf_prog_create_from_user+0x258/0x2b4
>   [c24379d0] [c027111c] do_seccomp+0x3dc/0x1890
>   [c2437ac0] [c001d8e0] system_call_exception+0x2dc/0x420
>   [c2437f30] [c00281ac] ret_from_syscall+0x0/0x2c
>   --- interrupt: c00 at 0x5a1274
>   NIP:  005a1274 LR: 006a3b3c CTR: 005296c8
>   REGS: c2437f40 TRAP: 0c00   Tainted: G        W           (6.13.0-rc6-PMacG4)
>   MSR:  0200f932 <VEC,EE,PR,FP,ME,IR,DR,RI>  CR: 24004422  XER: 00000000
> 
> [...]

Applied to powerpc/fixes.

[1/1] powerpc/code-patching: Fix KASAN hit by not flagging text patching area as VM_ALLOC
      https://git.kernel.org/powerpc/c/d262a192d38e527faa5984629aabda2e0d1c4f54

Thanks