> Hi Lorenzo, thanks for the quick fix.

Hi Mark,

thx for the review

> 
> Generally speaking, I think that instead of calling the bitmap library
> and accessing lflow->dpg_bitmap.map directly, you should probably add
> new functions to the dynamic_bitmap library to accomplish the same
> thing.
> 
> For this patch, that would mean adding
> dynamic_bitmap_is_set()
> dynamic_bitmap_or()
> dynamic_bitmap_count1()

ack, I will add them in v2.

> 
> Adding dynamic_bitmap_is_set() is a nice convenience function.
> 
> Adding dynamic_bitmap_or() and dynamic_bitmap_count1() can help to
> avoid errors since you no longer will need to pass a size argument to
> those functions. The internal dynamic bitmap library can use the
> db->capacity as its size. Since dynamic_bitmap_or() would deal with
> two dynamic bitmaps, you can even add an assertion to ensure that the
> two dynamic bitmaps are the same size.
> 
> I have a similar note below.
> 
> On Wed, Nov 12, 2025 at 10:02 AM Lorenzo Bianconi via dev
> <[email protected]> wrote:
> >
> > This allow easy bitmap resizing to avoid the following address sanitizer
> > crashes if we are exceeding bitmap allocated size. This issue can occurs
> > since IP lflow support for logical routers does not take into account
> > ovn_lflow bitmap resize.
> >
> > =================================================================
> > ==52991==ERROR: AddressSanitizer: heap-buffer-overflow on address 
> > 0x7bce82430100 at pc 0x0000004eae83 bp 0x7ffd7306f980 sp 0x7ffd7306f978
> > READ of size 8 at 0x7bce82430100 thread T0
> >     #0 0x0000004eae82 in bitmap_is_set ovn/ovs/lib/bitmap.h:91
> >     #1 0x0000004eae82 in lflow_table_add_lflow northd/lflow-mgr.c:765
> >     #2 0x00000046c075 in build_adm_ctrl_flows_for_lrouter 
> > northd/northd.c:13759
> >     #3 0x00000046c075 in build_lswitch_and_lrouter_iterate_by_lr 
> > northd/northd.c:18591
> >     #4 0x000000479805 in lflow_handle_northd_lr_changes 
> > northd/northd.c:19299
> >     #5 0x00000049bcc0 in lflow_northd_handler northd/en-lflow.c:158
> >     #6 0x000000508895 in engine_compute lib/inc-proc-eng.c:474
> >     #7 0x000000508895 in engine_run_node lib/inc-proc-eng.c:546
> >     #8 0x000000508895 in engine_run lib/inc-proc-eng.c:575
> >     #9 0x0000004e0cff in inc_proc_northd_run northd/inc-proc-northd.c:602
> >     #10 0x0000004077b4 in main northd/ovn-northd.c:1104
> >     #11 0x7fae83523574 in __libc_start_call_main (/lib64/libc.so.6+0x3574) 
> > (BuildId: 48c4b9b1efb1df15da8e787f489128bf31893317)
> >     #12 0x7fae83523627 in __libc_start_main@GLIBC_2.2.5 
> > (/lib64/libc.so.6+0x3627) (BuildId: 
> > 48c4b9b1efb1df15da8e787f489128bf31893317)
> >     #13 0x00000040ae74 in _start (ovn/northd/ovn-northd+0x40ae74) (BuildId: 
> > 5373e3f3823362d2c1a220082395cf8a9aae28bc)
> >
> > 0x7bce82430100 is located 0 bytes after 16-byte region 
> > [0x7bce824300f0,0x7bce82430100)
> > allocated by thread T0 here:
> >     #0 0x7fae83ee68a3 in calloc (/lib64/libasan.so.8+0xe68a3) (BuildId: 
> > cab80046dbc1c97c6e14490acc37d079701f8d9a)
> >     #1 0x00000077873e in xcalloc__ lib/util.c:125
> >     #2 0x00000077873e in xzalloc__ lib/util.c:135
> >     #3 0x00000077873e in xzalloc lib/util.c:169
> >     #4 0x0000004ea05b in bitmap_allocate ovn/ovs/lib/bitmap.h:51
> >     #5 0x0000004ea05b in ovn_lflow_init northd/lflow-mgr.c:901
> >     #6 0x0000004ea05b in do_ovn_lflow_add northd/lflow-mgr.c:1028
> >     #7 0x0000004ea05b in lflow_table_add_lflow northd/lflow-mgr.c:730
> >     #8 0x00000046c075 in build_adm_ctrl_flows_for_lrouter 
> > northd/northd.c:13759
> >     #9 0x00000046c075 in build_lswitch_and_lrouter_iterate_by_lr 
> > northd/northd.c:18591
> >     #10 0x000000479805 in lflow_handle_northd_lr_changes 
> > northd/northd.c:19299
> >     #11 0x00000049bcc0 in lflow_northd_handler northd/en-lflow.c:158
> >     #12 0x000000508895 in engine_compute lib/inc-proc-eng.c:474
> >     #13 0x000000508895 in engine_run_node lib/inc-proc-eng.c:546
> >     #14 0x000000508895 in engine_run lib/inc-proc-eng.c:575
> >     #15 0x0000004e0cff in inc_proc_northd_run northd/inc-proc-northd.c:602
> >     #16 0x0000004077b4 in main northd/ovn-northd.c:1104
> >     #17 0x7fae83523574 in __libc_start_call_main (/lib64/libc.so.6+0x3574) 
> > (BuildId: 48c4b9b1efb1df15da8e787f489128bf31893317)
> >     #18 0x7fae83523627 in __libc_start_main@GLIBC_2.2.5 
> > (/lib64/libc.so.6+0x3627) (BuildId: 
> > 48c4b9b1efb1df15da8e787f489128bf31893317)
> >     #19 0x00000040ae74 in _start (ovn/northd/ovn-northd+0x40ae74) (BuildId: 
> > 5373e3f3823362d2c1a220082395cf8a9aae28bc)
> >
> > Fixes: 9ec96d0d85b6 ("northd: Add and delete logical routers in en-lflow 
> > engine node.")
> > Fixes: f22a005f8935 ("northd: Convert datapath array into vector.")
> > Reported-at: https://issues.redhat.com/browse/FDP-2643
> > Signed-off-by: Lorenzo Bianconi <[email protected]>
> > ---
> >  northd/lflow-mgr.c | 30 +++++++++++++++---------------
> >  1 file changed, 15 insertions(+), 15 deletions(-)
> >
> > diff --git a/northd/lflow-mgr.c b/northd/lflow-mgr.c
> > index e60f248f3..3af36c7fd 100644
> > --- a/northd/lflow-mgr.c
> > +++ b/northd/lflow-mgr.c
> > @@ -173,7 +173,7 @@ struct ovn_lflow {
> >      struct hmap_node hmap_node;
> >
> >      struct ovn_datapath *od;     /* 'logical_datapath' in SB schema.  */
> > -    unsigned long *dpg_bitmap;   /* Bitmap of all datapaths by their 
> > 'index'.*/
> > +    struct dynamic_bitmap dpg_bitmap;
> >      enum ovn_stage stage;
> >      uint16_t priority;
> >      char *match;
> > @@ -636,13 +636,13 @@ lflow_ref_unlink_lflows(struct lflow_ref *lflow_ref)
> >              BITMAP_FOR_EACH_1 (index, lrn->dpgrp_bitmap_len,
> >                                 lrn->dpgrp_bitmap) {
> >                  if (dp_refcnt_release(&lrn->lflow->dp_refcnts_map, index)) 
> > {
> > -                    bitmap_set0(lrn->lflow->dpg_bitmap, index);
> > +                    dynamic_bitmap_set0(&lrn->lflow->dpg_bitmap, index);
> >                  }
> >              }
> >          } else {
> >              if (dp_refcnt_release(&lrn->lflow->dp_refcnts_map,
> >                                    lrn->dp_index)) {
> > -                bitmap_set0(lrn->lflow->dpg_bitmap, lrn->dp_index);
> > +                dynamic_bitmap_set0(&lrn->lflow->dpg_bitmap, 
> > lrn->dp_index);
> >              }
> >          }
> >
> > @@ -756,13 +756,13 @@ lflow_table_add_lflow(struct lflow_table *lflow_table,
> >                  size_t index;
> >                  BITMAP_FOR_EACH_1 (index, dp_bitmap_len, dp_bitmap) {
> >                      /* Allocate a reference counter only if already used. 
> > */
> > -                    if (bitmap_is_set(lflow->dpg_bitmap, index)) {
> > +                    if (bitmap_is_set(lflow->dpg_bitmap.map, index)) {
> >                          dp_refcnt_use(&lflow->dp_refcnts_map, index);
> >                      }
> >                  }
> >              } else {
> >                  /* Allocate a reference counter only if already used. */
> > -                if (bitmap_is_set(lflow->dpg_bitmap, lrn->dp_index)) {
> > +                if (bitmap_is_set(lflow->dpg_bitmap.map, lrn->dp_index)) {
> >                      dp_refcnt_use(&lflow->dp_refcnts_map, lrn->dp_index);
> >                  }
> >              }
> > @@ -898,7 +898,7 @@ ovn_lflow_init(struct ovn_lflow *lflow, struct 
> > ovn_datapath *od,
> >                 char *stage_hint, const char *where,
> >                 const char *flow_desc, struct uuid sbuuid)
> >  {
> > -    lflow->dpg_bitmap = bitmap_allocate(dp_bitmap_len);
> > +    dynamic_bitmap_alloc(&lflow->dpg_bitmap, dp_bitmap_len);
> >      lflow->od = od;
> >      lflow->stage = stage;
> >      lflow->priority = priority;
> > @@ -982,7 +982,7 @@ static void
> >  ovn_lflow_destroy(struct lflow_table *lflow_table, struct ovn_lflow *lflow)
> >  {
> >      hmap_remove(&lflow_table->entries, &lflow->hmap_node);
> > -    bitmap_free(lflow->dpg_bitmap);
> > +    dynamic_bitmap_free(&lflow->dpg_bitmap);
> >      free(lflow->match);
> >      free(lflow->actions);
> >      free(lflow->io_port);
> > @@ -1014,6 +1014,7 @@ do_ovn_lflow_add(struct lflow_table *lflow_table, 
> > size_t dp_bitmap_len,
> >      old_lflow = ovn_lflow_find(&lflow_table->entries, stage,
> >                                 priority, match, actions, ctrl_meter, hash);
> >      if (old_lflow) {
> > +        dynamic_bitmap_realloc(&old_lflow->dpg_bitmap, dp_bitmap_len);
> >          if (old_lflow->sync_state != LFLOW_STALE) {
> >              return old_lflow;
> >          }
> > @@ -1074,14 +1075,13 @@ sync_lflow_to_sb(struct ovn_lflow *lflow,
> >          is_switch = false;
> >      }
> >
> > -    lflow->n_ods = bitmap_count1(lflow->dpg_bitmap, n_datapaths);
> > +    lflow->n_ods = bitmap_count1(lflow->dpg_bitmap.map, n_datapaths);
> >      ovs_assert(lflow->n_ods);
> >
> >      if (lflow->n_ods == 1) {
> >          /* There is only one datapath, so it should be moved out of the
> >           * group to a single 'od'. */
> > -        size_t index = bitmap_scan(lflow->dpg_bitmap, true, 0,
> > -                                    n_datapaths);
> > +        size_t index = dynamic_bitmap_scan(&lflow->dpg_bitmap, true, 0);
> >
> >          lflow->od = datapaths_array[index];
> >          lflow->dpg = NULL;
> > @@ -1180,7 +1180,7 @@ sync_lflow_to_sb(struct ovn_lflow *lflow,
> >      } else {
> >          sbrec_logical_flow_set_logical_datapath(sbflow, NULL);
> >          lflow->dpg = ovn_dp_group_get(dp_groups, lflow->n_ods,
> > -                                      lflow->dpg_bitmap,
> > +                                      lflow->dpg_bitmap.map,
> >                                        n_datapaths);
> >          if (lflow->dpg) {
> >              /* Update the dpg's sb dp_group. */
> > @@ -1213,7 +1213,7 @@ sync_lflow_to_sb(struct ovn_lflow *lflow,
> >          } else {
> >              lflow->dpg = ovn_dp_group_create(
> >                                  ovnsb_txn, dp_groups, sbrec_dp_group,
> > -                                lflow->n_ods, lflow->dpg_bitmap,
> > +                                lflow->n_ods, lflow->dpg_bitmap.map,
> >                                  n_datapaths, is_switch,
> 
> Like with my other suggestion, you could change ovn_dp_group_create()
> to take a dynamic bitmap instead of a bitmap and its size. This way,
> we always ensure we use the correct size since we'll use the dynamic
> bitmap's internal "capacity" field.

I think this is not correct since, if you take a look to patch 2/2,
bitmap_len can be bigger than dpg->bitmap.capacity running ovn_dp_group_find()
so in this case we need to reallocate according to the new size.

Regards,
Lorenzo

> 
> 
> >                                  ls_datapaths,
> >                                  lr_datapaths);
> > @@ -1312,10 +1312,10 @@ ovn_dp_group_add_with_reference(struct ovn_lflow 
> > *lflow_ref,
> >      OVS_REQUIRES(fake_hash_mutex)
> >  {
> >      if (od) {
> > -        bitmap_set1(lflow_ref->dpg_bitmap, od->index);
> > +        dynamic_bitmap_set1(&lflow_ref->dpg_bitmap, od->index);
> >      }
> >      if (dp_bitmap) {
> > -        bitmap_or(lflow_ref->dpg_bitmap, dp_bitmap, bitmap_len);
> > +        bitmap_or(lflow_ref->dpg_bitmap.map, dp_bitmap, bitmap_len);
> >      }
> >  }
> >
> > @@ -1347,7 +1347,7 @@ lflow_ref_sync_lflows__(struct lflow_ref  *lflow_ref,
> >              n_datapaths = ods_size(lr_datapaths);
> >          }
> >
> > -        size_t n_ods = bitmap_count1(lflow->dpg_bitmap, n_datapaths);
> > +        size_t n_ods = bitmap_count1(lflow->dpg_bitmap.map, n_datapaths);
> >
> >          if (n_ods) {
> >              if (!sync_lflow_to_sb(lflow, ovnsb_txn, lflow_table, 
> > ls_datapaths,
> > --
> > 2.51.1
> >
> > _______________________________________________
> > dev mailing list
> > [email protected]
> > https://mail.openvswitch.org/mailman/listinfo/ovs-dev
> >
> 
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