The 04/20/2021 13:44, Firo Yang wrote: Hi Kazu-san, > This new O option is very useful to specify the head node > offset for listing linked list whose head node embedded has a > different offset to other node, e.g. dentry.d_subdirs(the head node) > and dentry.d_child. > > Signed-off-by: Firo Yang <[email protected]> > --- > defs.h | 1 + > help.c | 12 +++++++++++- > tools.c | 30 +++++++++++++++++++++++++++--- > 3 files changed, 39 insertions(+), 4 deletions(-) > > diff --git a/defs.h b/defs.h > index 35b983a..764facf 100644 > --- a/defs.h > +++ b/defs.h > @@ -2605,6 +2605,7 @@ struct list_data { /* generic structure > used by do_list() to walk */ > #define LIST_PARSE_MEMBER (VERBOSE << 13) > #define LIST_READ_MEMBER (VERBOSE << 14) > #define LIST_BRENT_ALGO (VERBOSE << 15) > +#define LIST_HEAD_OFFSET_ENTERED (VERBOSE << 16) > > struct tree_data { > ulong flags; > diff --git a/help.c b/help.c > index 531f50a..b561f3b 100644 > --- a/help.c > +++ b/help.c > @@ -5716,7 +5716,7 @@ char *help__list[] = { > "list", > "linked list", > "[[-o] offset][-e end][-[s|S] struct[.member[,member] [-l offset]] -[x|d]]" > -"\n [-r|-B] [-h|-H] start", > +"\n [-r|-B] [-h [-O head_offset]|-H] start", > " ", > " This command dumps the contents of a linked list. The entries in a > linked", > " list are typically data structures that are tied together in one of two", > @@ -5800,6 +5800,16 @@ char *help__list[] = { > " -S struct Similar to -s, but instead of parsing gdb output, member > values", > " are read directly from memory, so the command works much > faster", > " for 1-, 2-, 4-, and 8-byte members.", > +" -O offset The -O option works only with -h option.", > +" It is used for specifying the offset of head node embedded > in a", > +" structure, like dentry.d_subdirs or > cgroup_subsys_state.children.", > +" The offset may be entered in either of two manners:", > +"", > +" 1. \"structure.member\" format.", > +" 2. a number of bytes.", > +"", > +" You can use it like the following:", > +" list -O <head node offset> -o <node offset> -h start -s > <...>", > " -l offset Only used in conjunction with -s, if the start address > argument", > " is a pointer to an embedded list head (or any other similar > list", > " linkage structure whose first member points to the next > linkage", > diff --git a/tools.c b/tools.c > index a26b101..792a567 100644 > --- a/tools.c > +++ b/tools.c > @@ -3343,6 +3343,7 @@ void > cmd_list(void) > { > int c; > + long head_member_offset; /* offset for head like denty.d_subdirs */ > struct list_data list_data, *ld; > struct datatype_member struct_member, *sm; > struct syment *sp; > @@ -3353,7 +3354,7 @@ cmd_list(void) > BZERO(ld, sizeof(struct list_data)); > struct_list_offset = 0; > > - while ((c = getopt(argcnt, args, "BHhrs:S:e:o:xdl:")) != EOF) { > + while ((c = getopt(argcnt, args, "BHhrs:S:e:o:O:xdl:")) != EOF) { > switch(c) > { > case 'B': > @@ -3394,6 +3395,24 @@ cmd_list(void) > optarg); > break; > > + case 'O': > + if (ld->flags & LIST_HEAD_OFFSET_ENTERED) > + error(FATAL, > + "offset value %d (0x%lx) already entered\n", > + head_member_offset, > head_member_offset); > + else if (IS_A_NUMBER(optarg)) > + head_member_offset = stol(optarg, > + FAULT_ON_ERROR, NULL); > + else if (arg_to_datatype(optarg, > + sm, RETURN_ON_ERROR) > 1) > + head_member_offset = sm->member_offset; > + else > + error(FATAL, "invalid -O argument: %s\n", > + optarg); > + > + ld->flags |= LIST_HEAD_OFFSET_ENTERED; > + break; > + > case 'o': > if (ld->flags & LIST_OFFSET_ENTERED) > error(FATAL, > @@ -3599,8 +3618,13 @@ next_arg: > fprintf(fp, "(empty)\n"); > return; > } > - } else > - ld->start += ld->list_head_offset; > + } else { > + if (ld->flags & LIST_HEAD_OFFSET_ENTERED) > + readmem(ld->start + head_member_offset, KVADDR, > + &ld->start, sizeof(void *), "LIST_HEAD > contents", FAULT_ON_ERROR); > + else > + ld->start += ld->list_head_offset; > + } > } > > ld->flags &= ~(LIST_OFFSET_ENTERED|LIST_START_ENTERED); > -- > 2.30.2 >
I am not sure whether this patch is considered helpful or not. Could you please share some thoughts? Thanks, Firo -- Crash-utility mailing list [email protected] https://listman.redhat.com/mailman/listinfo/crash-utility
