On Thu, Dec 05, 2024 at 08:36:33AM +0100, Uros Bizjak wrote: > On Wed, Dec 4, 2024 at 4:52 PM Laura Nao <laura.nao@xxxxxxxxxxxxx> wrote: > > > > On 11/15/24 18:17, Laura Nao wrote: > > > I managed to reproduce the issue locally and I've uploaded the vmlinux[1] > > > (stripped of DWARF data) and vmlinux.raw[2] files, as well as one of the > > > modules[3] and its btf data[4] extracted with: > > > > > > bpftool -B vmlinux btf dump file cros_kbd_led_backlight.ko > cros_kbd_led_backlight.ko.raw > > > > > > Looking again at the logs[5], I've noticed the following is reported: > > > > > > [ 0.415885] BPF: type_id=115803 offset=177920 size=1152 > > > [ 0.416029] BPF: > > > [ 0.416083] BPF: Invalid offset > > > [ 0.416165] BPF: > > > > > > There are two different definitions of rcu_data in '.data..percpu', one > > > is a struct and the other is an integer: > > > > > > type_id=115801 offset=177920 size=1152 (VAR 'rcu_data') > > > type_id=115803 offset=177920 size=1152 (VAR 'rcu_data') > > > > > > [115801] VAR 'rcu_data' type_id=115572, linkage=static > > > [115803] VAR 'rcu_data' type_id=1, linkage=static > > > > > > [115572] STRUCT 'rcu_data' size=1152 vlen=69 > > > [1] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none) > > > > > > I assume that's not expected, correct? > > > > > > I'll dig a bit deeper and report back if I can find anything else. > > > > I ran a bisection, and it appears the culprit commit is: > > https://lore.kernel.org/all/20241021080856.48746-2-ubizjak@xxxxxxxxx/ > > > > Hi Uros, do you have any suggestions or insights on resolving this issue? > > There is a stray ";" at the end of the #define, perhaps this makes a difference: > > +#define PERCPU_PTR(__p) \ > + (typeof(*(__p)) __force __kernel *)(__p); > + > > and SHIFT_PERCPU_PTR macro now expands to: > > RELOC_HIDE((typeof(*(p)) __force __kernel *)(p);, (offset)) > > A follow-up patch in the series changes PERCPU_PTR macro to: > > #define PERCPU_PTR(__p) \ > ({ \ > unsigned long __pcpu_ptr = (__force unsigned long)(__p); \ > (typeof(*(__p)) __force __kernel *)(__pcpu_ptr); \ > }) > > so this should again correctly cast the value. Hm, I saw a similar bug but with pahole 1.28. My kernel complains about BTF invalid offset: [ 7.785788] BPF: type_id=2394 offset=0 size=1 [ 7.786411] BPF: [ 7.786703] BPF: Invalid offset [ 7.787119] BPF: Dumping the vmlinux (there is no module invovled), I saw it is related to percpu pointer too: [2394] VAR '__pcpu_unique_cpu_hw_events' type_id=2, linkage=global ... [163643] DATASEC '.data..percpu' size=2123280 vlen=808 type_id=2393 offset=0 size=1 (VAR '__pcpu_scope_cpu_hw_events') type_id=2394 offset=0 size=1 (VAR '__pcpu_unique_cpu_hw_events') ... I compiled and installed the latest pahole from its git repo: $ pahole --version v1.28 Thanks.
