Re: [Crash-utility] [PATCH] Fix for 'struct -o' option to display the offsets of struct fields

Hi Lianbo, On 2022/05/26 16:07, Lianbo Jiang wrote: > Currently, the 'struct -o' command does not display the offsets > of struct fields like this: > > crash> struct page -ox ffffce98870a0d40 > struct page { > [ffffce98870a0d40] unsigned long flags; > union { > struct {...}; > struct {...}; > struct {...}; > struct {...}; > struct {...}; > struct {...}; > struct {...}; > [ffffce98870a0d48] struct callback_head callback_head; > }; > ... > } > SIZE: 0x40 Good catch! > > The gdb-10.2 added a new option '/o' for the 'ptype' command, which > prints the offsets and sizes of struct fields, let's use it now to > fix the above issue. but isn't there another gdb option or setting to show their details? (gdb) ptype struct page type = struct page { unsigned long flags; union { struct {...}; struct {...}; struct {...}; ... If there is no setting other than '/o', it's a bit strange UI design, I think.. (although I cannot find so far..) Also the 'ptype /o' overdoes unfolding struct members, and extra spaces and lines are printed with the patch: * crash-7.3.2 crash-7.3.2> struct address_space struct address_space { struct inode *host; struct xarray i_pages; atomic_t i_mmap_writable; struct rb_root_cached i_mmap; struct rw_semaphore i_mmap_rwsem; unsigned long nrpages; ... crash-7.3.2> struct -o address_space struct address_space { [0] struct inode *host; [8] struct xarray i_pages; [32] atomic_t i_mmap_writable; [40] struct rb_root_cached i_mmap; [56] struct rw_semaphore i_mmap_rwsem; [96] unsigned long nrpages; * With the patch crash-dev> struct address_space struct address_space { struct inode *host; struct xarray { spinlock_t xa_lock; gfp_t xa_flags; void *xa_head; size_t xarray_size_rh; struct xarray_rh { <no data fields> } _rh; } i_pages; atomic_t i_mmap_writable; struct rb_root_cached { struct rb_root { struct rb_node *rb_node; ... crash-dev> struct -o address_space struct address_space { [0] struct inode *host; struct xarray { spinlock_t xa_lock; gfp_t xa_flags; void *xa_head; size_t xarray_size_rh; struct xarray_rh { <no data fields> } _rh; [8] } i_pages; [32] atomic_t i_mmap_writable; struct rb_root_cached { struct rb_root { struct rb_node *rb_node; ... task_struct also looks wrong: crash-dev> struct -o task_struct struct task_struct { struct thread_info { [36] unsigned long flags; u32 status; [0] } thread_info; [16] volatile long state; [24] void *stack; ... If no another gdb setting, we will need to rewrite the parser. So first, I'd like to know whether there is no another setting.