Re: [Crash-utility] [PATCH] crash: Use '?' for kernel module symbols type

Hi Dave, Sorry for late reply, was busy with something else. On 3/7/19 8:50 PM, Dave Anderson wrote: >>> We are using ELFXX_sym->st_info directly as the 'type' of symbol, >>> which is wrong, because st_info contains numeric value which needs >>> to be mapped to appropriate type character. >> >> I'm confused here. If I dump each module symbol's st_info fields as they >> are >> being read/initialized, they always contain the unsigned char ASCII value >> for >> either 't', 'r', 'd', 'b' or 'w'. What do you mean that it needs to be >> mapped >> to the appropriate type character? > > And for that matter, since your patch marks all module symbols as type '?', > commands like "dis" fail to recognize a module text address as such, and > therefore fails to complete the command. For example, without the patch: > > crash> sym dm_put > ffffffffa0000520 (t) dm_put [dm_mod] > crash> dis dm_put > 0xffffffffa0000520 <dm_put>: nopl 0x0(%rax,%rax,1) [FTRACE NOP] > 0xffffffffa0000525 <dm_put+5>: push %rbp > 0xffffffffa0000526 <dm_put+6>: mov %rsp,%rbp > 0xffffffffa0000529 <dm_put+9>: lock decl 0x180(%rdi) > 0xffffffffa0000530 <dm_put+16>: pop %rbp > 0xffffffffa0000531 <dm_put+17>: retq > crash> The problem happens only with module symbols, not with kallsyms. crash> sym -M c008000007810000 MODULE START: crc32c_vpmsum c008000007810000 (^R) __crc32c_vpmsum c008000007810670 (^B) crc32c_vpmsum_cra_init c008000007810690 (^B) crc32c_vpmsum_setkey