Re: [Crash-utility] [PATCH v2] Fix 'waitq' command for 4.13 and later kernels

-----Original Message----- > The wait queue structs and members were renamed in 4.13 in commits: > > ac6424b981bc ("sched/wait: Rename wait_queue_t => wait_queue_entry_t") > 9d9d676f595b ("sched/wait: Standardize internal naming of wait-queue heads") > 2055da97389a ("sched/wait: Disambiguate wq_entry->task_list and wq_head->task_list naming") > > Add support to the 'waitq' command for these more recent kernels. > > Signed-off-by: Greg Edwards <gedwards(a)ddn.com&gt; > --- > Changes from v1: > * address Kazu's review feedback Thanks for the update. > > defs.h | 4 ++++ > kernel.c | 23 +++++++++++++++++++++-- > symbols.c | 10 +++++++++- > 3 files changed, 34 insertions(+), 3 deletions(-) > > diff --git a/defs.h b/defs.h > index 42c8074e6ac6..6bb00e29d811 100644 > --- a/defs.h > +++ b/defs.h > @@ -2138,6 +2138,9 @@ struct offset_table { /* stash of commonly-used offsets */ > long atomic_long_t_counter; > long block_device_bd_device; > long block_device_bd_stats; > + long wait_queue_entry_private; > + long wait_queue_head_head; > + long wait_queue_entry_entry; > }; > > struct size_table { /* stash of commonly-used sizes */ > @@ -2300,6 +2303,7 @@ struct size_table { /* stash of commonly-used sizes */ > long printk_info; > long printk_ringbuffer; > long prb_desc; > + long wait_queue_entry; > }; > > struct array_table { > diff --git a/kernel.c b/kernel.c > index 528f6ee524f6..6a379229713d 100644 > --- a/kernel.c > +++ b/kernel.c > @@ -615,7 +615,15 @@ kernel_init() > kt->flags |= TVEC_BASES_V1; > > STRUCT_SIZE_INIT(__wait_queue, "__wait_queue"); > - if (VALID_STRUCT(__wait_queue)) { > + STRUCT_SIZE_INIT(wait_queue_entry, "wait_queue_entry"); > + if (VALID_STRUCT(wait_queue_entry)) { > + MEMBER_OFFSET_INIT(wait_queue_entry_private, > + "wait_queue_entry", "private"); > + MEMBER_OFFSET_INIT(wait_queue_head_head, > + "wait_queue_head", "head"); > + MEMBER_OFFSET_INIT(wait_queue_entry_entry, > + "wait_queue_entry", "entry"); > + } else if (VALID_STRUCT(__wait_queue)) { > if (MEMBER_EXISTS("__wait_queue", "task")) > MEMBER_OFFSET_INIT(__wait_queue_task, > "__wait_queue", "task"); > @@ -9397,9 +9405,20 @@ dump_waitq(ulong wq, char *wq_name) > ld->list_head_offset = OFFSET(__wait_queue_task_list); > ld->member_offset = next_offset; > > + start_index = 1; > + } else if (VALID_STRUCT(wait_queue_entry)) { > + ulong head_offset; > + > + next_offset = OFFSET(list_head_next); > + task_offset = OFFSET(wait_queue_entry_private); > + head_offset = OFFSET(wait_queue_head_head); > + ld->end = ld->start = wq + head_offset + next_offset; > + ld->list_head_offset = OFFSET(wait_queue_entry_entry); > + ld->member_offset = next_offset; > + > start_index = 1; > } else { > - return; > + error(FATAL, "cannot determine wait queue structure\n"); oh, I should have checked the replacement.. this emits compilation warnings: $ make clean ; make warn ... cc -c -g -DX86_64 -DLZO -DSNAPPY -DGDB_7_6 kernel.c -Wall -O2 -Wstrict-prototypes -Wmissing-prototypes -fstack-protector -Wformat-security kernel.c: In function 'cmd_waitq': kernel.c:9380:6: warning: 'start_index' may be used uninitialized in this function [-Wmaybe-uninitialized] int start_index; /* where to start in wq array */ ^~~~~~~~~~~ kernel.c:9454:22: warning: 'task_offset' may be used uninitialized in this function [-Wmaybe-uninitialized] readmem(wq_list[i] + task_offset, KVADDR, &task, ~~~~~~~~~~~^~~~~~~~~~~~~ kernel.c:9378:8: note: 'task_offset' was declared here ulong task_offset; /* offset of task in wq element */ ^~~~~~~~~~~ Hmm, in this case, I'd like to put the return back when merging. Lianbo, is this ok? } else { error(FATAL, "cannot determine wait queue structure\n");

+ return; /* just to suppress useless compilation warnings */ } Otherwise, the patch looks good to me. Acked-by: Kazuhito Hagio <k-hagio-ab(a)nec.com&gt; Thanks, Kazu > } > > hq_open(); > diff --git a/symbols.c b/symbols.c > index 370d4c3e8ac0..bdc1cac98348 100644 > --- a/symbols.c > +++ b/symbols.c > @@ -9817,7 +9817,13 @@ dump_offset_table(char *spec, ulong makestruct) > OFFSET(__wait_queue_head_task_list)); > fprintf(fp, " __wait_queue_task_list: %ld\n", > OFFSET(__wait_queue_task_list)); > - > + fprintf(fp, " wait_queue_entry_private: %ld\n", > + OFFSET(wait_queue_entry_private)); > + fprintf(fp, " wait_queue_head_head: %ld\n", > + OFFSET(wait_queue_head_head)); > + fprintf(fp, " wait_queue_entry_entry: %ld\n", > + OFFSET(wait_queue_entry_entry)); > + > fprintf(fp, " pglist_data_node_zones: %ld\n", > OFFSET(pglist_data_node_zones)); > fprintf(fp, " pglist_data_node_mem_map: %ld\n", > @@ -10717,6 +10723,8 @@ dump_offset_table(char *spec, ulong makestruct) > fprintf(fp, " wait_queue: %ld\n", SIZE(wait_queue)); > fprintf(fp, " __wait_queue: %ld\n", > SIZE(__wait_queue)); > + fprintf(fp, " wait_queue_entry: %ld\n", > + SIZE(wait_queue_entry)); > fprintf(fp, " device: %ld\n", SIZE(device)); > fprintf(fp, " net_device: %ld\n", SIZE(net_device)); > > -- > 2.32.0