Changing idr_replace's 'id' argument to 'unsigned long' works for all
callers. Callers which passed a negative ID now get -ENOENT instead of
-EINVAL. No callers relied on this error value.
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Propagate extack on removal of offloaded filter.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pass offload flags to the new implementation of
tc_cls_common_offload_init(). Extack will now only
be set if user requested skip_sw.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
cls_bpf now guarantees that only device-bound programs are
allowed with skip_sw. The drivers no longer pay attention to
flags on filter load, therefore the bpf_offload member can be
removed. If flags are needed again they should probably be
added to struct tc_cls_common_offload instead.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Rename the tc_cls_common_offload_init() helper function to
tc_cls_common_offload_init_deprecated() and add a new implementation
which also takes flags argument. We will only set extack if flags
indicate that offload is forced (skip_sw) otherwise driver errors
should be ignored, as they don't influence the overall filter
installation.
Note that we need the tc_skip_hw() helper for new version, therefore
it is added later in the file.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Propagate extack to cls->destroy callbacks when called from
non-error paths. On error paths pass NULL to avoid overwriting
the failure message.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add extack support for hardware offload of classifiers. In order
to achieve this, a pointer to a struct netlink_ext_ack is added to the
struct tc_cls_common_offload that is passed to the callback for setting
up the classifier. Function tc_cls_common_offload_init() is updated to
support initialization of this new attribute.
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pass the extack pointer obtained in the `->change()` filter operation to
cls_bpf_offload() and then to cls_bpf_offload_cmd(). This makes it
possible to use this extack pointer in drivers offloading BPF programs
in a future patch.
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The BPF verifier conflict was some minor contextual issue.
The TUN conflict was less trivial. Cong Wang fixed a memory leak of
tfile->tx_array in 'net'. This is an skb_array. But meanwhile in
net-next tun changed tfile->tx_arry into tfile->tx_ring which is a
ptr_ring.
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds extack support for classifier delete callback api. This
prepares to handle extack support inside each specific classifier
implementation.
Cc: David Ahern <dsahern@gmail.com>
Signed-off-by: Alexander Aring <aring@mojatatu.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The tcf_exts_validate function calls the act api change callback. For
preparing extack support for act api, this patch adds the extack as
parameter for this function which is common used in cls implementations.
Furthermore the tcf_exts_validate will call action init callback which
prepares the TC action subsystem for extack support.
Cc: David Ahern <dsahern@gmail.com>
Signed-off-by: Alexander Aring <aring@mojatatu.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds extack support for classifier change callback api. This
prepares to handle extack support inside each specific classifier
implementation.
Cc: David Ahern <dsahern@gmail.com>
Signed-off-by: Alexander Aring <aring@mojatatu.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Running the following sequence is currently broken:
# tc qdisc add dev foo clsact
# tc filter replace dev foo ingress prio 1 handle 1 bpf da obj bar.o
# tc filter replace dev foo ingress prio 1 handle 1 bpf da obj bar.o
RTNETLINK answers: Invalid argument
The normal expectation on kernel side is that the second command
succeeds replacing the existing program. However, what happens is
in cls_bpf_change(), we bail out with err in the second run in
cls_bpf_offload(). The EINVAL comes directly in cls_bpf_offload()
when comparing prog vs oldprog's gen_flags. In case of above
replace the new prog's gen_flags are 0, but the old ones are 8,
which means TCA_CLS_FLAGS_NOT_IN_HW is set (e.g. drivers not having
cls_bpf offload).
Fix 102740bd94 ("cls_bpf: fix offload assumptions after callback
conversion") in the following way: gen_flags from user space passed
down via netlink cannot include status flags like TCA_CLS_FLAGS_IN_HW
or TCA_CLS_FLAGS_NOT_IN_HW as opposed to oldprog that we previously
loaded. Therefore, it doesn't make any sense to include them in the
gen_flags comparison with the new prog before we even attempt to
offload. Thus, lets fix this before 4.15 goes out.
Fixes: 102740bd94 ("cls_bpf: fix offload assumptions after callback conversion")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
During block bind, we need to check tc offload feature. If it is
disabled yet still the block contains offloaded filters, forbid the
bind. Also forbid to register callback for a block that already
contains offloaded filters, as the play back is not supported now.
For keeping track of offloaded filters there is a new counter
introduced, alongside with couple of helpers called from cls_* code.
These helpers set and clear TCA_CLS_FLAGS_IN_HW flag.
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Couple of classifiers call netif_keep_dst directly on q->dev. That is
not possible to do directly for shared blocke where multiple qdiscs are
owning the block. So introduce a infrastructure to keep track of the
block owners in list and use this list to implement block variant of
netif_keep_dst.
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
cls_bpf used to take care of tracking what offload state a filter
is in, i.e. it would track if offload request succeeded or not.
This information would then be used to issue correct requests to
the driver, e.g. requests for statistics only on offloaded filters,
removing only filters which were offloaded, using add instead of
replace if previous filter was not added etc.
This tracking of offload state no longer functions with the new
callback infrastructure. There could be multiple entities trying
to offload the same filter.
Throw out all the tracking and corresponding commands and simply
pass to the drivers both old and new bpf program. Drivers will
have to deal with offload state tracking by themselves.
Fixes: 3f7889c4c7 ("net: sched: cls_bpf: call block callbacks for offload")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When cls_bpf offload was added it seemed like a good idea to
call cls_bpf_delete_prog() instead of extending the error
handling path, since the software state is fully initialized
at that point. This handling of errors without jumping to
the end of the function is error prone, as proven by later
commit missing that extra call to __cls_bpf_delete_prog().
__cls_bpf_delete_prog() is now expected to be invoked with
a reference on exts->net or the field zeroed out. The call
on the offload's error patch does not fullfil this requirement,
leading to each error stealing a reference on net namespace.
Create a function undoing what cls_bpf_set_parms() did and
use it from __cls_bpf_delete_prog() and the error path.
Fixes: aae2c35ec8 ("cls_bpf: use tcf_exts_get_net() before call_rcu()")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
With TC shared block changes we can't depend on correct netdev
pointer being available in cls_bpf. Move the device validation
to the driver. Core will only make sure that offloaded programs
are always attached in the driver (or in HW by the driver). We
trust that drivers which implement offload callbacks will perform
necessary checks.
Moving the checks to the driver is generally a useful thing,
in practice the check should be against a switchdev instance,
not a netdev, given that most ASICs will probably allow using
the same program on many ports.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Simple cases of overlapping changes in the packet scheduler.
Must easier to resolve this time.
Which probably means that I screwed it up somehow.
Signed-off-by: David S. Miller <davem@davemloft.net>
Hold netns refcnt before call_rcu() and release it after
the tcf_exts_destroy() is done.
Note, on ->destroy() path we have to respect the return value
of tcf_exts_get_net(), on other paths it should always return
true, so we don't need to care.
Cc: Lucas Bates <lucasb@mojatatu.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
If TC program is loaded with skip_sw flag, we should allow
the device-specific programs to be accepted.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently gen_flags is being operated on by a logical && operator rather
than a bitwise & operator. This looks incorrect as these should be bit
flag operations. Fix this.
Detected by CoverityScan, CID#1460305 ("Logical vs. bitwise operator")
Fixes: 3f7889c4c7 ("net: sched: cls_bpf: call block callbacks for offload)
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Several conflicts here.
NFP driver bug fix adding nfp_netdev_is_nfp_repr() check to
nfp_fl_output() needed some adjustments because the code block is in
an else block now.
Parallel additions to net/pkt_cls.h and net/sch_generic.h
A bug fix in __tcp_retransmit_skb() conflicted with some of
the rbtree changes in net-next.
The tc action RCU callback fixes in 'net' had some overlap with some
of the recent tcf_block reworking.
Signed-off-by: David S. Miller <davem@davemloft.net>
Defer the tcf_exts_destroy() in RCU callback to
tc filter workqueue and get RTNL lock.
Reported-by: Chris Mi <chrism@mellanox.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
All drivers are converted to use block callbacks for TC_SETUP_CLS*.
So it is now safe to remove the calls to ndo_setup_tc from cls_*
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use the newly introduced callbacks infrastructure and call block
callbacks alongside with the existing per-netdev ndo_setup_tc.
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Instead of calling cls_bpf_get() in a loop to find
a unused handle, just switch to idr API to allocate
new handles.
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Chris Mi <chrism@mellanox.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Just do the rename into bpf_compute_data_pointers() as we'll add
one more pointer here to recompute.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
TC filters when used as classifiers are bound to TC classes.
However, there is a hidden difference when adding them in different
orders:
1. If we add tc classes before its filters, everything is fine.
Logically, the classes exist before we specify their ID's in
filters, it is easy to bind them together, just as in the current
code base.
2. If we add tc filters before the tc classes they bind, we have to
do dynamic lookup in fast path. What's worse, this happens all
the time not just once, because on fast path tcf_result is passed
on stack, there is no way to propagate back to the one in tc filters.
This hidden difference hurts performance silently if we have many tc
classes in hierarchy.
This patch intends to close this gap by doing the reverse binding when
we create a new class, in this case we can actually search all the
filters in its parent, match and fixup by classid. And because
tcf_result is specific to each type of tc filter, we have to introduce
a new ops for each filter to tell how to bind the class.
Note, we still can NOT totally get rid of those class lookup in
->enqueue() because cgroup and flow filters have no way to determine
the classid at setup time, they still have to go through dynamic lookup.
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
cops->tcf_cl_offload is no longer needed, as the drivers check what they
can and cannot offload using the classid identify helpers. So remove this.
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now we use 'unsigned long fh' as a pointer in every place,
it is safe to convert it to a void pointer now. This gets
rid of many casts to pointer.
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Get rid of struct tc_to_netdev which is now just unnecessary container
and rather pass per-type structures down to drivers directly.
Along with that, consolidate the naming of per-type structure variables
in cls_*.
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
As ndo_setup_tc is generic offload op for whole tc subsystem, does not
really make sense to have cls-specific args. So move them under
cls_common structurure which is embedded in all cls structs.
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since the type is always present, push it to be a separate argument to
ndo_setup_tc. On the way, name the type enum and use it for arg type.
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
As the prog struct was allocated right before cls_bpf_set_parms call,
no need to use tcf_exts_change to do atomic change, and we can just
fill-up the unused exts struct directly by tcf_exts_validate.
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The name cls_bpf_modify_existing is highly misleading, as it indeed does
not modify anything existing. It does not modify at all.
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
In order to be able to retrieve the attached programs from cls_bpf
and act_bpf, we need to expose the prog ids via netlink so that
an application can later on get an fd based on the id through the
BPF_PROG_GET_FD_BY_ID command, and dump related prog info via
BPF_OBJ_GET_INFO_BY_FD command for bpf(2).
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
We need to push the chain index down to the drivers, so they have the
information to which chain the rule belongs. For now, no driver supports
multichain offload, so only chain 0 is supported. This is needed to
prevent chain squashes during offload for now. Later this will be used
to implement multichain offload.
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
There is need to instruct the HW offloaded path to push certain matched
packets to cpu/kernel for further analysis. So this patch introduces a
new TRAP control action to TC.
For kernel datapath, this action does not make much sense. So with the
same logic as in HW, new TRAP behaves similar to STOLEN. The skb is just
dropped in the datapath (and virtually ejected to an upper level, which
does not exist in case of kernel).
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Yotam Gigi <yotamg@mellanox.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
We could have a race condition where in ->classify() path we
dereference tp->root and meanwhile a parallel ->destroy() makes it
a NULL. Daniel cured this bug in commit d936377414
("net, sched: respect rcu grace period on cls destruction").
This happens when ->destroy() is called for deleting a filter to
check if we are the last one in tp, this tp is still linked and
visible at that time. The root cause of this problem is the semantic
of ->destroy(), it does two things (for non-force case):
1) check if tp is empty
2) if tp is empty we could really destroy it
and its caller, if cares, needs to check its return value to see if it
is really destroyed. Therefore we can't unlink tp unless we know it is
empty.
As suggested by Daniel, we could actually move the test logic to ->delete()
so that we can safely unlink tp after ->delete() tells us the last one is
just deleted and before ->destroy().
Fixes: 1e052be69d ("net_sched: destroy proto tp when all filters are gone")
Cc: Roi Dayan <roid@mellanox.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pass the new extended ACK reporting struct to all of the generic
netlink parsing functions. For now, pass NULL in almost all callers
(except for some in the core.)
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
BPF classifier support for the "in hw" offloading flags.
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Reviewed-by: Amir Vadai <amir@vadai.me>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 7bd509e311 ("bpf: add prog_digest and expose it via
fdinfo/netlink") was recently discussed, partially due to
admittedly suboptimal name of "prog_digest" in combination
with sha1 hash usage, thus inevitably and rightfully concerns
about its security in terms of collision resistance were
raised with regards to use-cases.
The intended use cases are for debugging resp. introspection
only for providing a stable "tag" over the instruction sequence
that both kernel and user space can calculate independently.
It's not usable at all for making a security relevant decision.
So collisions where two different instruction sequences generate
the same tag can happen, but ideally at a rather low rate. The
"tag" will be dumped in hex and is short enough to introspect
in tracepoints or kallsyms output along with other data such
as stack trace, etc. Thus, this patch performs a rename into
prog_tag and truncates the tag to a short output (64 bits) to
make it obvious it's not collision-free.
Should in future a hash or facility be needed with a security
relevant focus, then we can think about requirements, constraints,
etc that would fit to that situation. For now, rework the exposed
parts for the current use cases as long as nothing has been
released yet. Tested on x86_64 and s390x.
Fixes: 7bd509e311 ("bpf: add prog_digest and expose it via fdinfo/netlink")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
When loading a BPF program via bpf(2), calculate the digest over
the program's instruction stream and store it in struct bpf_prog's
digest member. This is done at a point in time before any instructions
are rewritten by the verifier. Any unstable map file descriptor
number part of the imm field will be zeroed for the hash.
fdinfo example output for progs:
# cat /proc/1590/fdinfo/5
pos: 0
flags: 02000002
mnt_id: 11
prog_type: 1
prog_jited: 1
prog_digest: b27e8b06da22707513aa97363dfb11c7c3675d28
memlock: 4096
When programs are pinned and retrieved by an ELF loader, the loader
can check the program's digest through fdinfo and compare it against
one that was generated over the ELF file's program section to see
if the program needs to be reloaded. Furthermore, this can also be
exposed through other means such as netlink in case of a tc cls/act
dump (or xdp in future), but also through tracepoints or other
facilities to identify the program. Other than that, the digest can
also serve as a base name for the work in progress kallsyms support
of programs. The digest doesn't depend/select the crypto layer, since
we need to keep dependencies to a minimum. iproute2 will get support
for this facility.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 18cdb37ebf ("net: sched: do not use tcf_proto 'tp' argument from
call_rcu") removed the last usage of tp from cls_bpf_delete_prog(), so also
remove it from the function as argument to not give a wrong impression. tp
is illegal to access from this callback, since it could already have been
freed.
Refactor the deletion code a bit, so that cls_bpf_destroy() can call into
the same code for prog deletion as cls_bpf_delete() op, instead of having
it unnecessarily duplicated.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Couple conflicts resolved here:
1) In the MACB driver, a bug fix to properly initialize the
RX tail pointer properly overlapped with some changes
to support variable sized rings.
2) In XGBE we had a "CONFIG_PM" --> "CONFIG_PM_SLEEP" fix
overlapping with a reorganization of the driver to support
ACPI, OF, as well as PCI variants of the chip.
3) In 'net' we had several probe error path bug fixes to the
stmmac driver, meanwhile a lot of this code was cleaned up
and reorganized in 'net-next'.
4) The cls_flower classifier obtained a helper function in
'net-next' called __fl_delete() and this overlapped with
Daniel Borkamann's bug fix to use RCU for object destruction
in 'net'. It also overlapped with Jiri's change to guard
the rhashtable_remove_fast() call with a check against
tc_skip_sw().
5) In mlx4, a revert bug fix in 'net' overlapped with some
unrelated changes in 'net-next'.
6) In geneve, a stale header pointer after pskb_expand_head()
bug fix in 'net' overlapped with a large reorganization of
the same code in 'net-next'. Since the 'net-next' code no
longer had the bug in question, there was nothing to do
other than to simply take the 'net-next' hunks.
Signed-off-by: David S. Miller <davem@davemloft.net>
Roi reported a crash in flower where tp->root was NULL in ->classify()
callbacks. Reason is that in ->destroy() tp->root is set to NULL via
RCU_INIT_POINTER(). It's problematic for some of the classifiers, because
this doesn't respect RCU grace period for them, and as a result, still
outstanding readers from tc_classify() will try to blindly dereference
a NULL tp->root.
The tp->root object is strictly private to the classifier implementation
and holds internal data the core such as tc_ctl_tfilter() doesn't know
about. Within some classifiers, such as cls_bpf, cls_basic, etc, tp->root
is only checked for NULL in ->get() callback, but nowhere else. This is
misleading and seemed to be copied from old classifier code that was not
cleaned up properly. For example, d3fa76ee6b ("[NET_SCHED]: cls_basic:
fix NULL pointer dereference") moved tp->root initialization into ->init()
routine, where before it was part of ->change(), so ->get() had to deal
with tp->root being NULL back then, so that was indeed a valid case, after
d3fa76ee6b, not really anymore. We used to set tp->root to NULL long
ago in ->destroy(), see 47a1a1d4be ("pkt_sched: remove unnecessary xchg()
in packet classifiers"); but the NULLifying was reintroduced with the
RCUification, but it's not correct for every classifier implementation.
In the cases that are fixed here with one exception of cls_cgroup, tp->root
object is allocated and initialized inside ->init() callback, which is always
performed at a point in time after we allocate a new tp, which means tp and
thus tp->root was not globally visible in the tp chain yet (see tc_ctl_tfilter()).
Also, on destruction tp->root is strictly kfree_rcu()'ed in ->destroy()
handler, same for the tp which is kfree_rcu()'ed right when we return
from ->destroy() in tcf_destroy(). This means, the head object's lifetime
for such classifiers is always tied to the tp lifetime. The RCU callback
invocation for the two kfree_rcu() could be out of order, but that's fine
since both are independent.
Dropping the RCU_INIT_POINTER(tp->root, NULL) for these classifiers here
means that 1) we don't need a useless NULL check in fast-path and, 2) that
outstanding readers of that tp in tc_classify() can still execute under
respect with RCU grace period as it is actually expected.
Things that haven't been touched here: cls_fw and cls_route. They each
handle tp->root being NULL in ->classify() path for historic reasons, so
their ->destroy() implementation can stay as is. If someone actually
cares, they could get cleaned up at some point to avoid the test in fast
path. cls_u32 doesn't set tp->root to NULL. For cls_rsvp, I just added a
!head should anyone actually be using/testing it, so it at least aligns with
cls_fw and cls_route. For cls_flower we additionally need to defer rhashtable
destruction (to a sleepable context) after RCU grace period as concurrent
readers might still access it. (Note that in this case we need to hold module
reference to keep work callback address intact, since we only wait on module
unload for all call_rcu()s to finish.)
This fixes one race to bring RCU grace period guarantees back. Next step
as worked on by Cong however is to fix 1e052be69d ("net_sched: destroy
proto tp when all filters are gone") to get the order of unlinking the tp
in tc_ctl_tfilter() for the RTM_DELTFILTER case right by moving
RCU_INIT_POINTER() before tcf_destroy() and let the notification for
removal be done through the prior ->delete() callback. Both are independant
issues. Once we have that right, we can then clean tp->root up for a number
of classifiers by not making them RCU pointers, which requires a new callback
(->uninit) that is triggered from tp's RCU callback, where we just kfree()
tp->root from there.
Fixes: 1f947bf151 ("net: sched: rcu'ify cls_bpf")
Fixes: 9888faefe1 ("net: sched: cls_basic use RCU")
Fixes: 70da9f0bf9 ("net: sched: cls_flow use RCU")
Fixes: 77b9900ef5 ("tc: introduce Flower classifier")
Fixes: bf3994d2ed ("net/sched: introduce Match-all classifier")
Fixes: 952313bd62 ("net: sched: cls_cgroup use RCU")
Reported-by: Roi Dayan <roid@mellanox.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Roi Dayan <roid@mellanox.com>
Cc: Jiri Pirko <jiri@mellanox.com>
Acked-by: John Fastabend <john.r.fastabend@intel.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
After setup we don't need to keep user space fd number around anymore, as
it also has no useful meaning for anyone, just remove it.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
