Date: Wed, 8 Jan 2025 12:30:11 +1300 From: Tao Liu <ltao(a)redhat.com&gt; Subject: [Crash-utility] Re: [PATCH] Fix "net -a" option on Linux 6.13 and later kernels To: HAGIO KAZUHITO(萩尾 一仁) <k-hagio-ab(a)nec.com&gt; Cc: &quot;devel(a)lists.crash-utility.osci.io&quot; <devel(a)lists.crash-utility.osci.io&gt; Message-ID: <CAO7dBbVYFpdtgMOvtnxp4MJJB_p4GyG= 2_je7yMt33H40JmZZA(a)mail.gmail.com&gt; Content-Type: text/plain; charset="UTF-8" Hi Kazu, Thanks for the fix, the patch LGTM, so ack.

Thanks, Tao Liu On Tue, Jan 7, 2025 at 3:46 PM HAGIO KAZUHITO(萩尾 一仁) <k-hagio-ab(a)nec.com&gt; wrote: > > From: Kazuhito Hagio <k-hagio-ab(a)nec.com&gt; > > Kernel commit e4e3fd0a99d5 ("Merge branch 'improve-neigh_flush_dev-performance'") > and its patch set, which are contained in Linux 6.13 and later kernels, > removed neigh_hash_table.hash_buckets and neighbour.next members, and > introduced neigh_hash_table.hash_heads and neighbour.hash members > instead with the hlist implementation. > > Without the patch, the "net -a" option fails with the following error: > > crash> net -a > > net: invalid structure member offset: neigh_table_hash_buckets > FILE: net.c LINE: 701 FUNCTION: dump_arp() > ... > > Signed-off-by: Kazuhito Hagio <k-hagio-ab(a)nec.com&gt; > --- > defs.h | 2 ++ > net.c | 26 +++++++++++++++++++++----- > symbols.c | 2 ++ > 3 files changed, 25 insertions(+), 5 deletions(-) > > diff --git a/defs.h b/defs.h > index d8d378ef94b1..8378cbab2f73 100644 > --- a/defs.h > +++ b/defs.h > @@ -2269,6 +2269,8 @@ struct offset_table { /* stash of commonly-used offsets */ > long task_struct_thread_context_x26; > long task_struct_thread_context_x27; > long task_struct_thread_context_x28; > + long neigh_table_hash_heads; > + long neighbour_hash; > }; > > struct size_table { /* stash of commonly-used sizes */ > diff --git a/net.c b/net.c > index 31d3f2bf7c2f..4e14f19fc097 100644 > --- a/net.c > +++ b/net.c > @@ -169,6 +169,11 @@ net_init(void) > "neigh_hash_table", "hash_shift"); > MEMBER_OFFSET_INIT(neigh_table_hash_buckets, > "neigh_hash_table", "hash_buckets"); > + /* Linux 6.13 and later */ > + if (INVALID_MEMBER(neigh_table_hash_buckets)) { > + MEMBER_OFFSET_INIT(neigh_table_hash_heads, "neigh_hash_table", "hash_heads"); > + MEMBER_OFFSET_INIT(neighbour_hash, "neighbour", "hash"); > + } > } else { > MEMBER_OFFSET_INIT(neigh_table_hash_buckets, > "neigh_table", "hash_buckets"); > @@ -698,9 +703,13 @@ dump_arp(void) > "neigh_table key_len", FAULT_ON_ERROR); > > if (VALID_MEMBER(neigh_table_nht_ptr)) { > - readmem(nht + OFFSET(neigh_table_hash_buckets), > - KVADDR, &hash, sizeof(hash), > - "neigh_hash_table hash_buckets ptr", FAULT_ON_ERROR); > + /* Linux 6.13 and later */ > + if (VALID_MEMBER(neigh_table_hash_heads)) > + readmem(nht + OFFSET(neigh_table_hash_heads), KVADDR, &hash, > + sizeof(hash), "neigh_hash_table hash_heads ptr", FAULT_ON_ERROR); > + else > + readmem(nht + OFFSET(neigh_table_hash_buckets), KVADDR, &hash, > + sizeof(hash), "neigh_hash_table hash_buckets ptr", FAULT_ON_ERROR); > > readmem(hash, KVADDR, hash_buckets, hash_bytes, > "neigh_hash_table hash_buckets", FAULT_ON_ERROR); > @@ -831,8 +840,15 @@ print_neighbour_q(ulong addr, int key_len) > > arp_state_to_flags(state); > > - readmem(addr + OFFSET(neighbour_next), KVADDR, > - &addr, sizeof(addr), "neighbour next", FAULT_ON_ERROR); > + /* Linux 6.13 and later kernels use hlist. */ > + if (VALID_MEMBER(neighbour_hash)) { > + readmem(addr + OFFSET(neighbour_hash), KVADDR, &addr, > + sizeof(addr), "neighbour hash", FAULT_ON_ERROR); > + if (addr) > + addr -= OFFSET(neighbour_hash); > + } else > + readmem(addr + OFFSET(neighbour_next), KVADDR, &addr, > + sizeof(addr), "neighbour next", FAULT_ON_ERROR); > } > > FREEBUF(ha_buf); > diff --git a/symbols.c b/symbols.c > index a3cd0f3f6e1f..0b63e11fa567 100644 > --- a/symbols.c > +++ b/symbols.c > @@ -11028,6 +11028,7 @@ dump_offset_table(char *spec, ulong makestruct) > > fprintf(fp, " neighbour_next: %ld\n", > OFFSET(neighbour_next)); > + fprintf(fp, " neighbour_hash: %ld\n", OFFSET(neighbour_hash)); > fprintf(fp, " neighbour_primary_key: %ld\n", > OFFSET(neighbour_primary_key)); > fprintf(fp, " neighbour_ha: %ld\n", > @@ -11038,6 +11039,7 @@ dump_offset_table(char *spec, ulong makestruct) > OFFSET(neighbour_nud_state)); > fprintf(fp, " neigh_table_hash_buckets: %ld\n", > OFFSET(neigh_table_hash_buckets)); > + fprintf(fp, " neigh_table_hash_heads: %ld\n", OFFSET(neigh_table_hash_heads)); > fprintf(fp, " neigh_table_hash_mask: %ld\n", > OFFSET(neigh_table_hash_mask)); > fprintf(fp, " neigh_table_hash_shift: %ld\n", > -- > 2.31.1