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  1. 10 Jun, 2024 9 commits
    • Florian Westphal's avatar
      net: tcp: un-pin the tw_timer · c75ad7c7
      Florian Westphal authored 
      After previous patch, even if timer fires immediately on another CPU,
context that schedules the timer now holds the ehash spinlock, so timer
cannot reap tw socket until ehash lock is released.

BH disable is moved into hashdance_schedule.
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      c75ad7c7
    • Valentin Schneider's avatar
      net: tcp/dccp: prepare for tw_timer un-pinning · b334b924
      Valentin Schneider authored 
      The TCP timewait timer is proving to be problematic for setups where
scheduler CPU isolation is achieved at runtime via cpusets (as opposed to
statically via isolcpus=domains).

What happens there is a CPU goes through tcp_time_wait(), arming the
time_wait timer, then gets isolated. TCP_TIMEWAIT_LEN later, the timer
fires, causing interference for the now-isolated CPU. This is conceptually
similar to the issue described in commit e02b9312 ("workqueue: Unbind
kworkers before sending them to exit()")

Move inet_twsk_schedule() to within inet_twsk_hashdance(), with the ehash
lock held. Expand the lock's critical section from inet_twsk_kill() to
inet_twsk_deschedule_put(), serializing the scheduling vs descheduling of
the timer. IOW, this prevents the following race:

			     tcp_time_wait()
			       inet_twsk_hashdance()
  inet_twsk_deschedule_put()
    del_timer_sync()
			       inet_twsk_schedule()

Thanks to Paolo Abeni for suggesting to leverage the ehash lock.

This also restores a comment from commit ec94c269 ("tcp/dccp: avoid
one atomic operation for timewait hashdance") as inet_twsk_hashdance() had
a "Step 1" and "Step 3" comment, but the "Step 2" had gone missing.

inet_twsk_deschedule_put() now acquires the ehash spinlock to synchronize
with inet_twsk_hashdance_schedule().

To ease possible regression search, actual un-pin is done in next patch.

Link: https://lore.kernel.org/all/ZPhpfMjSiHVjQkTk@localhost.localdomain/Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarValentin Schneider <vschneid@redhat.com>
Co-developed-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      b334b924
    • David S. Miller's avatar
      Merge branch 'mlxsw-acl-fixes' · 8d466c8f
      David S. Miller authored 
      Petr Machata says:

====================
mlxsw: ACL fixes

Ido Schimmel writes:

Patches #1-#3 fix various spelling mistakes I noticed while working on
the code base.

Patch #4 fixes a general protection fault by bailing out when the error
occurs and warning.

Patch #5 fixes the warning.

Patch #6 fixes ACL scale regression and firmware errors.

See the commit messages for more info.
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      8d466c8f
    • Ido Schimmel's avatar
      mlxsw: spectrum_acl: Fix ACL scale regression and firmware errors · 75d8d7a6
      Ido Schimmel authored 
      ACLs that reside in the algorithmic TCAM (A-TCAM) in Spectrum-2 and
newer ASICs can share the same mask if their masks only differ in up to
8 consecutive bits. For example, consider the following filters:

 # tc filter add dev swp1 ingress pref 1 proto ip flower dst_ip 192.0.2.0/24 action drop
 # tc filter add dev swp1 ingress pref 1 proto ip flower dst_ip 198.51.100.128/25 action drop

The second filter can use the same mask as the first (dst_ip/24) with a
delta of 1 bit.

However, the above only works because the two filters have different
values in the common unmasked part (dst_ip/24). When entries have the
same value in the common unmasked part they create undesired collisions
in the device since many entries now have the same key. This leads to
firmware errors such as [1] and to a reduced scale.

Fix by adjusting the hash table key to only include the value in the
common unmasked part. That is, without including the delta bits. That
way the driver will detect the collision during filter insertion and
spill the filter into the circuit TCAM (C-TCAM).

Add a test case that fails without the fix and adjust existing cases
that check C-TCAM spillage according to the above limitation.

[1]
mlxsw_spectrum2 0000:06:00.0: EMAD reg access failed (tid=3379b18a00003394,reg_id=3027(ptce3),type=write,status=8(resource not available))

Fixes: c22291f7 ("mlxsw: spectrum: acl: Implement delta for ERP")
Reported-by: default avatarAlexander Zubkov <green@qrator.net>
Signed-off-by: default avatarIdo Schimmel <idosch@nvidia.com>
Reviewed-by: default avatarAmit Cohen <amcohen@nvidia.com>
Tested-by: default avatarAlexander Zubkov <green@qrator.net>
Signed-off-by: default avatarPetr Machata <petrm@nvidia.com>
Reviewed-by: default avatarSimon Horman <horms@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      75d8d7a6
    • Ido Schimmel's avatar
      mlxsw: spectrum_acl_erp: Fix object nesting warning · 97d833ce
      Ido Schimmel authored 
      ACLs in Spectrum-2 and newer ASICs can reside in the algorithmic TCAM
(A-TCAM) or in the ordinary circuit TCAM (C-TCAM). The former can
contain more ACLs (i.e., tc filters), but the number of masks in each
region (i.e., tc chain) is limited.

In order to mitigate the effects of the above limitation, the device
allows filters to share a single mask if their masks only differ in up
to 8 consecutive bits. For example, dst_ip/25 can be represented using
dst_ip/24 with a delta of 1 bit. The C-TCAM does not have a limit on the
number of masks being used (and therefore does not support mask
aggregation), but can contain a limited number of filters.

The driver uses the "objagg" library to perform the mask aggregation by
passing it objects that consist of the filter's mask and whether the
filter is to be inserted into the A-TCAM or the C-TCAM since filters in
different TCAMs cannot share a mask.

The set of created objects is dependent on the insertion order of the
filters and is not necessarily optimal. Therefore, the driver will
periodically ask the library to compute a more optimal set ("hints") by
looking at all the existing objects.

When the library asks the driver whether two objects can be aggregated
the driver only compares the provided masks and ignores the A-TCAM /
C-TCAM indication. This is the right thing to do since the goal is to
move as many filters as possible to the A-TCAM. The driver also forbids
two identical masks from being aggregated since this can only happen if
one was intentionally put in the C-TCAM to avoid a conflict in the
A-TCAM.

The above can result in the following set of hints:

H1: {mask X, A-TCAM} -> H2: {mask Y, A-TCAM} // X is Y + delta
H3: {mask Y, C-TCAM} -> H4: {mask Z, A-TCAM} // Y is Z + delta

After getting the hints from the library the driver will start migrating
filters from one region to another while consulting the computed hints
and instructing the device to perform a lookup in both regions during
the transition.

Assuming a filter with mask X is being migrated into the A-TCAM in the
new region, the hints lookup will return H1. Since H2 is the parent of
H1, the library will try to find the object associated with it and
create it if necessary in which case another hints lookup (recursive)
will be performed. This hints lookup for {mask Y, A-TCAM} will either
return H2 or H3 since the driver passes the library an object comparison
function that ignores the A-TCAM / C-TCAM indication.

This can eventually lead to nested objects which are not supported by
the library [1].

Fix by removing the object comparison function from both the driver and
the library as the driver was the only user. That way the lookup will
only return exact matches.

I do not have a reliable reproducer that can reproduce the issue in a
timely manner, but before the fix the issue would reproduce in several
minutes and with the fix it does not reproduce in over an hour.

Note that the current usefulness of the hints is limited because they
include the C-TCAM indication and represent aggregation that cannot
actually happen. This will be addressed in net-next.

[1]
WARNING: CPU: 0 PID: 153 at lib/objagg.c:170 objagg_obj_parent_assign+0xb5/0xd0
Modules linked in:
CPU: 0 PID: 153 Comm: kworker/0:18 Not tainted 6.9.0-rc6-custom-g70fbc2c1c38b #42
Hardware name: Mellanox Technologies Ltd. MSN3700C/VMOD0008, BIOS 5.11 10/10/2018
Workqueue: mlxsw_core mlxsw_sp_acl_tcam_vregion_rehash_work
RIP: 0010:objagg_obj_parent_assign+0xb5/0xd0
[...]
Call Trace:
 <TASK>
 __objagg_obj_get+0x2bb/0x580
 objagg_obj_get+0xe/0x80
 mlxsw_sp_acl_erp_mask_get+0xb5/0xf0
 mlxsw_sp_acl_atcam_entry_add+0xe8/0x3c0
 mlxsw_sp_acl_tcam_entry_create+0x5e/0xa0
 mlxsw_sp_acl_tcam_vchunk_migrate_one+0x16b/0x270
 mlxsw_sp_acl_tcam_vregion_rehash_work+0xbe/0x510
 process_one_work+0x151/0x370

Fixes: 9069a381 ("lib: objagg: implement optimization hints assembly and use hints for object creation")
Signed-off-by: default avatarIdo Schimmel <idosch@nvidia.com>
Reviewed-by: default avatarAmit Cohen <amcohen@nvidia.com>
Tested-by: default avatarAlexander Zubkov <green@qrator.net>
Signed-off-by: default avatarPetr Machata <petrm@nvidia.com>
Reviewed-by: default avatarSimon Horman <horms@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      97d833ce
    • Ido Schimmel's avatar
      lib: objagg: Fix general protection fault · b4a3a89f
      Ido Schimmel authored 
      The library supports aggregation of objects into other objects only if
the parent object does not have a parent itself. That is, nesting is not
supported.

Aggregation happens in two cases: Without and with hints, where hints
are a pre-computed recommendation on how to aggregate the provided
objects.

Nesting is not possible in the first case due to a check that prevents
it, but in the second case there is no check because the assumption is
that nesting cannot happen when creating objects based on hints. The
violation of this assumption leads to various warnings and eventually to
a general protection fault [1].

Before fixing the root cause, error out when nesting happens and warn.

[1]
general protection fault, probably for non-canonical address 0xdead000000000d90: 0000 [#1] PREEMPT SMP PTI
CPU: 1 PID: 1083 Comm: kworker/1:9 Tainted: G        W          6.9.0-rc6-custom-gd9b4f1cca7fb #7
Hardware name: Mellanox Technologies Ltd. MSN3700/VMOD0005, BIOS 5.11 01/06/2019
Workqueue: mlxsw_core mlxsw_sp_acl_tcam_vregion_rehash_work
RIP: 0010:mlxsw_sp_acl_erp_bf_insert+0x25/0x80
[...]
Call Trace:
 <TASK>
 mlxsw_sp_acl_atcam_entry_add+0x256/0x3c0
 mlxsw_sp_acl_tcam_entry_create+0x5e/0xa0
 mlxsw_sp_acl_tcam_vchunk_migrate_one+0x16b/0x270
 mlxsw_sp_acl_tcam_vregion_rehash_work+0xbe/0x510
 process_one_work+0x151/0x370
 worker_thread+0x2cb/0x3e0
 kthread+0xd0/0x100
 ret_from_fork+0x34/0x50
 ret_from_fork_asm+0x1a/0x30
 </TASK>

Fixes: 9069a381 ("lib: objagg: implement optimization hints assembly and use hints for object creation")
Reported-by: default avatarAlexander Zubkov <green@qrator.net>
Signed-off-by: default avatarIdo Schimmel <idosch@nvidia.com>
Reviewed-by: default avatarAmit Cohen <amcohen@nvidia.com>
Tested-by: default avatarAlexander Zubkov <green@qrator.net>
Signed-off-by: default avatarPetr Machata <petrm@nvidia.com>
Reviewed-by: default avatarSimon Horman <horms@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      b4a3a89f
    • Ido Schimmel's avatar
      mlxsw: spectrum_acl_atcam: Fix wrong comment · 06fcdf24
      Ido Schimmel authored 
      The key is encoded, not encrypted.

Fixes: c22291f7 ("mlxsw: spectrum: acl: Implement delta for ERP")
Signed-off-by: default avatarIdo Schimmel <idosch@nvidia.com>
Reviewed-by: default avatarAmit Cohen <amcohen@nvidia.com>
Tested-by: default avatarAlexander Zubkov <green@qrator.net>
Signed-off-by: default avatarPetr Machata <petrm@nvidia.com>
Reviewed-by: default avatarSimon Horman <horms@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      06fcdf24
    • Ido Schimmel's avatar
      lib: test_objagg: Fix spelling · 2aad28ec
      Ido Schimmel authored 
      Fixes: 0a020d41 ("lib: introduce initial implementation of object aggregation manager")
Signed-off-by: default avatarIdo Schimmel <idosch@nvidia.com>
Reviewed-by: default avatarAmit Cohen <amcohen@nvidia.com>
Tested-by: default avatarAlexander Zubkov <green@qrator.net>
Signed-off-by: default avatarPetr Machata <petrm@nvidia.com>
Reviewed-by: default avatarSimon Horman <horms@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      2aad28ec
    • Ido Schimmel's avatar
      lib: objagg: Fix spelling · c1e156ae
      Ido Schimmel authored 
      Fixes: 0a020d41 ("lib: introduce initial implementation of object aggregation manager")
Signed-off-by: default avatarIdo Schimmel <idosch@nvidia.com>
Reviewed-by: default avatarAmit Cohen <amcohen@nvidia.com>
Tested-by: default avatarAlexander Zubkov <green@qrator.net>
Signed-off-by: default avatarPetr Machata <petrm@nvidia.com>
Reviewed-by: default avatarSimon Horman <horms@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      c1e156ae
  3. 09 Jun, 2024 3 commits
  5. 07 Jun, 2024 2 commits
  7. 06 Jun, 2024 26 commits
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