scripts/gdb: remove exception handling and refine print format

1. When we crash on a page, we want to check what happened on this
page instead of skipping this page by try-except block. Thus, removing
the try-except block.

2. Remove redundant comma and print the task name properly.

Link: https://lkml.kernel.org/r/20231127070404.4192-4-Kuan-Ying.Lee@mediatek.com
Signed-off-by: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Cc: Chinwen Chang <chinwen.chang@mediatek.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Qun-Wei Lin <qun-wei.lin@mediatek.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

scripts/gdb/page_owner: add page owner support

This GDB script prints page owner information for user to analyze the
memory usage or memory corruption issue.

Example output from an aarch64 system:

(gdb) lx-dump-page-owner --pfn 655360
page_owner tracks the page as allocated
Page last allocated via order 0, gfp_mask: 0x8, pid: 1, tgid: 1 ("swapper/0\000\000\000\000\000\000"), ts 1295948880 ns, free_ts 1011852016 ns
PFN: 655360, Flags: 0x3fffc0000000000
0xffff8000086ab964 <post_alloc_hook+452>: ldp x19, x20, [sp, #16]
0xffff80000862e4e0 <split_map_pages+344>: cbnz w22, 0xffff80000862e57c <split_map_pages+500>
0xffff8000086370c4 <isolate_freepages_range+556>: mov x0, x27
0xffff8000086bc1cc <alloc_contig_range+808>: mov x24, x0
0xffff80000877d6d8 <cma_alloc+772>: mov w1, w0
0xffff8000082c8d18 <dma_alloc_from_contiguous+104>: ldr x19, [sp, #16]
0xffff8000082ce0e8 <atomic_pool_expand+208>: mov x19, x0
0xffff80000c1e41b4 <__dma_atomic_pool_init+172>: Cannot access memory at address 0xffff80000c1e41b4
0xffff80000c1e4298 <dma_atomic_pool_init+92>: Cannot access memory at address 0xffff80000c1e4298
0xffff8000080161d4 <do_one_initcall+176>: mov w21, w0
0xffff80000c1c1b50 <kernel_init_freeable+952>: Cannot access memory at address 0xffff80000c1c1b50
0xffff80000acf87dc <kernel_init+36>: bl 0xffff8000081ab100 <async_synchronize_full>
0xffff800008018d00 <ret_from_fork+16>: mrs x28, sp_el0
page last free stack trace:
0xffff8000086a6e8c <free_unref_page_prepare+796>: mov w2, w23
0xffff8000086aee1c <free_unref_page+96>: tst w0, #0xff
0xffff8000086af3f8 <__free_pages+292>: ldp x19, x20, [sp, #16]
0xffff80000c1f3214 <init_cma_reserved_pageblock+220>: Cannot access memory at address 0xffff80000c1f3214
0xffff80000c20363c <cma_init_reserved_areas+1284>: Cannot access memory at address 0xffff80000c20363c
0xffff8000080161d4 <do_one_initcall+176>: mov w21, w0
0xffff80000c1c1b50 <kernel_init_freeable+952>: Cannot access memory at address 0xffff80000c1c1b50
0xffff80000acf87dc <kernel_init+36>: bl 0xffff8000081ab100 <async_synchronize_full>
0xffff800008018d00 <ret_from_fork+16>: mrs x28, sp_el0

Link: https://lkml.kernel.org/r/20230808083020.22254-7-Kuan-Ying.Lee@mediatek.com
Signed-off-by: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
Cc: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Cc: Chinwen Chang <chinwen.chang@mediatek.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Qun-Wei Lin <qun-wei.lin@mediatek.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>