On Thu, 17 Apr 2025 00:42:27 +0530, Hari Bathini wrote: > While r15 is clobbered always with PPC_FTRACE_OUT_OF_LINE, it is > not restored in livepatch sequence leading to not so obvious fails > like below: > > BUG: Unable to handle kernel data access on write at 0xc0000000000f9078 > Faulting instruction address: 0xc0000000018ff958 > Oops: Kernel access of bad area, sig: 11 [#1] > ... > NIP: c0000000018ff958 LR: c0000000018ff930 CTR: c0000000009c0790 > REGS: c00000005f2e7790 TRAP: 0300 Tainted: G K (6.14.0+) > MSR: 8000000000009033 <SF,EE,ME,IR,DR,RI,LE> CR: 2822880b XER: 20040000 > CFAR: c0000000008addc0 DAR: c0000000000f9078 DSISR: 0a000000 IRQMASK: 1 > GPR00: c0000000018f2584 c00000005f2e7a30 c00000000280a900 c000000017ffa488 > GPR04: 0000000000000008 0000000000000000 c0000000018f24fc 000000000000000d > GPR08: fffffffffffe0000 000000000000000d 0000000000000000 0000000000008000 > GPR12: c0000000009c0790 c000000017ffa480 c00000005f2e7c78 c0000000000f9070 > GPR16: c00000005f2e7c90 0000000000000000 0000000000000000 0000000000000000 > GPR20: 0000000000000000 c00000005f3efa80 c00000005f2e7c60 c00000005f2e7c88 > GPR24: c00000005f2e7c60 0000000000000001 c0000000000f9078 0000000000000000 > GPR28: 00007fff97960000 c000000017ffa480 0000000000000000 c0000000000f9078 > ... > Call Trace: > check_heap_object+0x34/0x390 (unreliable) > __mutex_unlock_slowpath.isra.0+0xe4/0x230 > seq_read_iter+0x430/0xa90 > proc_reg_read_iter+0xa4/0x200 > vfs_read+0x41c/0x510 > ksys_read+0xa4/0x190 > system_call_exception+0x1d0/0x440 > system_call_vectored_common+0x15c/0x2ec > > [...]
Applied to powerpc/next. [1/1] powerpc64/ftrace: fix clobbered r15 during livepatching https://git.kernel.org/powerpc/c/cb5b691f8273432297611863ac142e17119279e0 Thanks