111 Commits
Author SHA1 Message Date
Linus Torvalds bf4afc53b7 Convert 'alloc_obj' family to use the new default GFP_KERNEL argument
This was done entirely with mindless brute force, using

    git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
        xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'

to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.

Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.

For the same reason the 'flex' versions will be done as a separate
conversion.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2026-02-21 17:09:51 -08:00
Kees Cook 69050f8d6d treewide: Replace kmalloc with kmalloc_obj for non-scalar types
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:

Single allocations:	kmalloc(sizeof(TYPE), ...)
are replaced with:	kmalloc_obj(TYPE, ...)

Array allocations:	kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with:	kmalloc_objs(TYPE, COUNT, ...)

Flex array allocations:	kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with:	kmalloc_flex(*PTR, FAM, COUNT, ...)

(where TYPE may also be *VAR)

The resulting allocations no longer return "void *", instead returning
"TYPE *".

Signed-off-by: Kees Cook <kees@kernel.org>
2026-02-21 01:02:28 -08:00
Puranjay MohanandAlexei Starovoitov 7646c7afd9 bpf: Remove redundant KF_TRUSTED_ARGS flag from all kfuncs
Now that KF_TRUSTED_ARGS is the default for all kfuncs, remove the
explicit KF_TRUSTED_ARGS flag from all kfunc definitions and remove the
flag itself.

Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/r/20260102180038.2708325-3-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-01-02 12:04:28 -08:00
Jakub KicinskiandPaolo Abeni 1827f773e4 net: xdp: pass full flags to xdp_update_skb_shared_info()
xdp_update_skb_shared_info() needs to update skb state which
was maintained in xdp_buff / frame. Pass full flags into it,
instead of breaking it out bit by bit. We will need to add
a bit for unreadable frags (even tho XDP doesn't support
those the driver paths may be common), at which point almost
all call sites would become:

    xdp_update_skb_shared_info(skb, num_frags,
                               sinfo->xdp_frags_size,
                               MY_PAGE_SIZE * num_frags,
                               xdp_buff_is_frag_pfmemalloc(xdp),
                               xdp_buff_is_frag_unreadable(xdp));

Keep a helper for accessing the flags, in case we need to
transform them somehow in the future (e.g. to cover up xdp_buff
vs xdp_frame differences).

While we are touching call callers - rename the helper to
xdp_update_skb_frags_info(), previous name may have implied that
it's shinfo that's updated. We are updating flags in struct sk_buff
based on frags that got attched.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Jesper Dangaard Brouer <hawk@kernel.org>
Link: https://patch.msgid.link/20250905221539.2930285-2-kuba@kernel.org
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Reviewed-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-09-11 12:00:20 +02:00
Bui Quang MinhandPaolo Abeni 28fcb4b56f xsk: add missing virtual address conversion for page
In commit 7ead4405e0 ("xsk: convert xdp_copy_frags_from_zc() to use
page_pool_dev_alloc()"), when converting from netmem to page, I missed a
call to page_address() around skb_frag_page(frag) to get the virtual
address of the page. This commit uses skb_frag_address() helper to fix
the issue.

Fixes: 7ead4405e0 ("xsk: convert xdp_copy_frags_from_zc() to use page_pool_dev_alloc()")
Reviewed-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: Bui Quang Minh <minhquangbui99@gmail.com>
Link: https://patch.msgid.link/20250522040115.5057-1-minhquangbui99@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-05-27 11:46:47 +02:00
Sebastian Andrzej SiewiorandPaolo Abeni b9eef3391d xdp: Use nested-BH locking for system_page_pool
system_page_pool is a per-CPU variable and relies on disabled BH for its
locking. Without per-CPU locking in local_bh_disable() on PREEMPT_RT
this data structure requires explicit locking.

Make a struct with a page_pool member (original system_page_pool) and a
local_lock_t and use local_lock_nested_bh() for locking. This change
adds only lockdep coverage and does not alter the functional behaviour
for !PREEMPT_RT.

Cc: Andrew Lunn <andrew+netdev@lunn.ch>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jesper Dangaard Brouer <hawk@kernel.org>
Cc: John Fastabend <john.fastabend@gmail.com>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://patch.msgid.link/20250512092736.229935-6-bigeasy@linutronix.de
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-05-15 15:23:31 +02:00
Bui Quang MinhandJakub Kicinski 7ead4405e0 xsk: convert xdp_copy_frags_from_zc() to use page_pool_dev_alloc()
This commit makes xdp_copy_frags_from_zc() use page allocation API
page_pool_dev_alloc() instead of page_pool_dev_alloc_netmem() to avoid
possible confusion of the returned value.

Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Bui Quang Minh <minhquangbui99@gmail.com>
Link: https://patch.msgid.link/20250426081220.40689-3-minhquangbui99@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-04-29 14:26:26 -07:00
Bui Quang MinhandJakub Kicinski ebaebc5eaf xsk: respect the offsets when copying frags
In commit 560d958c6c ("xsk: add generic XSk &xdp_buff -> skb
conversion"), we introduce a helper to convert zerocopy xdp_buff to skb.
However, in the frag copy, we mistakenly ignore the frag's offset. This
commit adds the missing offset when copying frags in
xdp_copy_frags_from_zc(). This function is not used anywhere so no
backport is needed.

Signed-off-by: Bui Quang Minh <minhquangbui99@gmail.com>
Link: https://patch.msgid.link/20250426081220.40689-2-minhquangbui99@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-04-29 14:26:26 -07:00
Joshua WashingtonandJakub Kicinski 0e0a7e3719 xdp: create locked/unlocked instances of xdp redirect target setters
Commit 03df156dd3 ("xdp: double protect netdev->xdp_flags with
netdev->lock") introduces the netdev lock to xdp_set_features_flag().
The change includes a _locked version of the method, as it is possible
for a driver to have already acquired the netdev lock before calling
this helper. However, the same applies to
xdp_features_(set|clear)_redirect_flags(), which ends up calling the
unlocked version of xdp_set_features_flags() leading to deadlocks in
GVE, which grabs the netdev lock as part of its suspend, reset, and
shutdown processes:

[  833.265543] WARNING: possible recursive locking detected
[  833.270949] 6.15.0-rc1 #6 Tainted: G            E
[  833.276271] --------------------------------------------
[  833.281681] systemd-shutdow/1 is trying to acquire lock:
[  833.287090] ffff949d2b148c68 (&dev->lock){+.+.}-{4:4}, at: xdp_set_features_flag+0x29/0x90
[  833.295470]
[  833.295470] but task is already holding lock:
[  833.301400] ffff949d2b148c68 (&dev->lock){+.+.}-{4:4}, at: gve_shutdown+0x44/0x90 [gve]
[  833.309508]
[  833.309508] other info that might help us debug this:
[  833.316130]  Possible unsafe locking scenario:
[  833.316130]
[  833.322142]        CPU0
[  833.324681]        ----
[  833.327220]   lock(&dev->lock);
[  833.330455]   lock(&dev->lock);
[  833.333689]
[  833.333689]  *** DEADLOCK ***
[  833.333689]
[  833.339701]  May be due to missing lock nesting notation
[  833.339701]
[  833.346582] 5 locks held by systemd-shutdow/1:
[  833.351205]  #0: ffffffffa9c89130 (system_transition_mutex){+.+.}-{4:4}, at: __se_sys_reboot+0xe6/0x210
[  833.360695]  #1: ffff93b399e5c1b8 (&dev->mutex){....}-{4:4}, at: device_shutdown+0xb4/0x1f0
[  833.369144]  #2: ffff949d19a471b8 (&dev->mutex){....}-{4:4}, at: device_shutdown+0xc2/0x1f0
[  833.377603]  #3: ffffffffa9eca050 (rtnl_mutex){+.+.}-{4:4}, at: gve_shutdown+0x33/0x90 [gve]
[  833.386138]  #4: ffff949d2b148c68 (&dev->lock){+.+.}-{4:4}, at: gve_shutdown+0x44/0x90 [gve]

Introduce xdp_features_(set|clear)_redirect_target_locked() versions
which assume that the netdev lock has already been acquired before
setting the XDP feature flag and update GVE to use the locked version.

Fixes: 03df156dd3 ("xdp: double protect netdev->xdp_flags with netdev->lock")
Tested-by: Mina Almasry <almasrymina@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Harshitha Ramamurthy <hramamurthy@google.com>
Signed-off-by: Joshua Washington <joshwash@google.com>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20250422011643.3509287-1-joshwash@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-04-22 19:57:56 -07:00
Toke Høiland-JørgensenandJakub Kicinski cd3c93167d page_pool: Move pp_magic check into helper functions
Since we are about to stash some more information into the pp_magic
field, let's move the magic signature checks into a pair of helper
functions so it can be changed in one place.

Reviewed-by: Mina Almasry <almasrymina@google.com>
Tested-by: Yonglong Liu <liuyonglong@huawei.com>
Acked-by: Jesper Dangaard Brouer <hawk@kernel.org>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://patch.msgid.link/20250409-page-pool-track-dma-v9-1-6a9ef2e0cba8@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-04-14 16:30:29 -07:00
Jakub Kicinski 03df156dd3 xdp: double protect netdev->xdp_flags with netdev->lock
Protect xdp_features with netdev->lock. This way pure readers
no longer have to take rtnl_lock to access the field.

This includes calling NETDEV_XDP_FEAT_CHANGE under the lock.
Looks like that's fine for bonding, the only "real" listener,
it's the same as ethtool feature change.

In terms of normal drivers - only GVE need special consideration
(other drivers don't use instance lock or don't support XDP).
It calls xdp_set_features_flag() helper from gve_init_priv() which
in turn is called from gve_reset_recovery() (locked), or prior
to netdev registration. So switch to _locked.

Reviewed-by: Joe Damato <jdamato@fastly.com>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Acked-by: Harshitha Ramamurthy <hramamurthy@google.com>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20250408195956.412733-6-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-04-09 17:01:52 -07:00
Alexander LobakinandPaolo Abeni b696d289c0 xdp: remove xdp_alloc_skb_bulk()
The only user was veth, which now uses napi_skb_cache_get_bulk().
It's now preferred over a direct allocation and is exported as
well, so remove this one.

Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-02-27 14:03:52 +01:00
Jakub Kicinski 2ee738e90e Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR (net-6.13-rc8).

Conflicts:

drivers/net/ethernet/realtek/r8169_main.c
  1f691a1fc4 ("r8169: remove redundant hwmon support")
  152d00a913 ("r8169: simplify setting hwmon attribute visibility")
https://lore.kernel.org/20250115122152.760b4e8d@canb.auug.org.au

Adjacent changes:

drivers/net/ethernet/broadcom/bnxt/bnxt.c
  152f4da05a ("bnxt_en: add support for rx-copybreak ethtool command")
  f0aa6a37a3 ("eth: bnxt: always recalculate features after XDP clearing, fix null-deref")

drivers/net/ethernet/intel/ice/ice_type.h
  50327223a8 ("ice: add lock to protect low latency interface")
  dc26548d72 ("ice: Fix quad registers read on E825")

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-01-16 10:34:59 -08:00
Stanislav FomichevandJakub Kicinski 5ef44b3cb4 xsk: Bring back busy polling support
Commit 86e25f40aa ("net: napi: Add napi_config") moved napi->napi_id
assignment to a later point in time (napi_hash_add_with_id). This breaks
__xdp_rxq_info_reg which copies napi_id at an earlier time and now
stores 0 napi_id. It also makes sk_mark_napi_id_once_xdp and
__sk_mark_napi_id_once useless because they now work against 0 napi_id.
Since sk_busy_loop requires valid napi_id to busy-poll on, there is no way
to busy-poll AF_XDP sockets anymore.

Bring back the ability to busy-poll on XSK by resolving socket's napi_id
at bind time. This relies on relatively recent netif_queue_set_napi,
but (assume) at this point most popular drivers should have been converted.
This also removes per-tx/rx cycles which used to check and/or set
the napi_id value.

Confirmed by running a busy-polling AF_XDP socket
(github.com/fomichev/xskrtt) on mlx5 and looking at BusyPollRxPackets
from /proc/net/netstat.

Fixes: 86e25f40aa ("net: napi: Add napi_config")
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Link: https://patch.msgid.link/20250109003436.2829560-1-sdf@fomichev.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-01-10 18:07:56 -08:00
Alexander LobakinandJakub Kicinski 560d958c6c xsk: add generic XSk &xdp_buff -> skb conversion
Same as with converting &xdp_buff to skb on Rx, the code which allocates
a new skb and copies the XSk frame there is identical across the
drivers, so make it generic. This includes copying all the frags if they
are present in the original buff.
System percpu page_pools greatly improve XDP_PASS performance on XSk:
instead of page_alloc() + page_free(), the net core recycles the same
pages, so the only overhead left is memcpy()s. When the Page Pool is
not compiled in, the whole function is a return-NULL (but it always
gets selected when eBPF is enabled).
Note that the passed buff gets freed if the conversion is done w/o any
error, assuming you don't need this buffer after you convert it to an
skb.

Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Link: https://patch.msgid.link/20241218174435.1445282-6-aleksander.lobakin@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-12-19 19:51:14 -08:00
Alexander LobakinandJakub Kicinski 539c1fba1a xdp: add generic xdp_build_skb_from_buff()
The code which builds an skb from an &xdp_buff keeps multiplying itself
around the drivers with almost no changes. Let's try to stop that by
adding a generic function.
Unlike __xdp_build_skb_from_frame(), always allocate an skbuff head
using napi_build_skb() and make use of the available xdp_rxq pointer to
assign the Rx queue index. In case of PP-backed buffer, mark the skb to
be recycled, as every PP user's been switched to recycle skbs.

Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Link: https://patch.msgid.link/20241218174435.1445282-4-aleksander.lobakin@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-12-19 19:51:14 -08:00
Alexander LobakinandJakub Kicinski 68ddc8ae17 xdp: add generic xdp_buff_add_frag()
The code piece which would attach a frag to &xdp_buff is almost
identical across the drivers supporting XDP multi-buffer on Rx.
Make it a generic elegant "oneliner".
Also, I see lots of drivers calculating frags_truesize as
`xdp->frame_sz * nr_frags`. I can't say this is fully correct, since
frags might be backed by chunks of different sizes, especially with
stuff like the header split. Even page_pool_alloc() can give you two
different truesizes on two subsequent requests to allocate the same
buffer size. Add a field to &skb_shared_info (unionized as there's no
free slot currently on x86_64) to track the "true" truesize. It can
be used later when updating the skb.

Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Link: https://patch.msgid.link/20241218174435.1445282-3-aleksander.lobakin@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-12-19 19:51:13 -08:00
Alexander LobakinandJakub Kicinski 207ff83cec xdp: make __xdp_return() MP-agnostic
Currently, __xdp_return() takes pointer to the virtual memory to free
a buffer. Apart from that this sometimes provokes redundant
data <--> page conversions, taking data pointer effectively prevents
lots of XDP code to support non-page-backed buffers, as there's no
mapping for the non-host memory (data is always NULL).
Just convert it to always take netmem reference. For
xdp_return_{buff,frame*}(), this chops off one page_address() per each
frag and adds one virt_to_netmem() (same as virt_to_page()) per header
buffer. For __xdp_return() itself, it removes one virt_to_page() for
MEM_TYPE_PAGE_POOL and another one for MEM_TYPE_PAGE_ORDER0, adding
one page_address() for [not really common nowadays]
MEM_TYPE_PAGE_SHARED, but the main effect is that the abovementioned
functions won't die or memleak anymore if the frame has non-host memory
attached and will correctly free those.

Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Link: https://patch.msgid.link/20241211172649.761483-4-aleksander.lobakin@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-12-12 18:22:52 -08:00
Alexander LobakinandJakub Kicinski 56d95b0adf xdp: get rid of xdp_frame::mem.id
Initially, xdp_frame::mem.id was used to search for the corresponding
&page_pool to return the page correctly.
However, after that struct page was extended to have a direct pointer
to its PP (netmem has it as well), further keeping of this field makes
no sense. xdp_return_frame_bulk() still used it to do a lookup, and
this leftover is now removed.
Remove xdp_frame::mem and replace it with ::mem_type, as only memory
type still matters and we need to know it to be able to free the frame
correctly.
As a cute side effect, we can now make every scalar field in &xdp_frame
of 4 byte width, speeding up accesses to them.

Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Link: https://patch.msgid.link/20241211172649.761483-3-aleksander.lobakin@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-12-12 18:22:52 -08:00
Alexander LobakinandJakub Kicinski fcc680a647 page_pool: allow mixing PPs within one bulk
The main reason for this change was to allow mixing pages from different
&page_pools within one &xdp_buff/&xdp_frame. Why not? With stuff like
devmem and io_uring zerocopy Rx, it's required to have separate PPs for
header buffers and payload buffers.
Adjust xdp_return_frame_bulk() and page_pool_put_netmem_bulk(), so that
they won't be tied to a particular pool. Let the latter create a
separate bulk of pages which's PP is different from the first netmem of
the bulk and process it after the main loop.
This greatly optimizes xdp_return_frame_bulk(): no more hashtable
lookups and forced flushes on PP mismatch. Also make
xdp_flush_frame_bulk() inline, as it's just one if + function call + one
u32 read, not worth extending the call ladder.

Co-developed-by: Toke Høiland-Jørgensen <toke@redhat.com> # iterative
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Suggested-by: Jakub Kicinski <kuba@kernel.org> # while (count)
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Link: https://patch.msgid.link/20241211172649.761483-2-aleksander.lobakin@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-12-12 18:22:51 -08:00
Alexander LobakinandJakub Kicinski 024bfd2e9d page_pool: make page_pool_put_page_bulk() handle array of netmems
Currently, page_pool_put_page_bulk() indeed takes an array of pointers
to the data, not pages, despite the name. As one side effect, when
you're freeing frags from &skb_shared_info, xdp_return_frame_bulk()
converts page pointers to virtual addresses and then
page_pool_put_page_bulk() converts them back. Moreover, data pointers
assume every frag is placed in the host memory, making this function
non-universal.
Make page_pool_put_page_bulk() handle array of netmems. Pass frag
netmems directly and use virt_to_netmem() when freeing xdpf->data,
so that the PP core will then get the compound netmem and take care
of the rest.

Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://patch.msgid.link/20241203173733.3181246-9-aleksander.lobakin@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-12-05 18:41:07 -08:00
Alexander LobakinandJakub Kicinski 9e25dd9d65 xsk: allow attaching XSk pool via xdp_rxq_info_reg_mem_model()
When you register an XSk pool as XDP Rxq info memory model, you then
need to manually attach it after the registration.
Let the user combine both actions into one by just passing a pointer
to the pool directly to xdp_rxq_info_reg_mem_model(), which will take
care of calling xsk_pool_set_rxq_info(). This looks similar to how a
&page_pool gets registered and reduce repeating driver code.

Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Link: https://patch.msgid.link/20241203173733.3181246-6-aleksander.lobakin@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-12-05 18:41:07 -08:00
Alexander LobakinandJakub Kicinski f65966fe01 xdp: allow attaching already registered memory model to xdp_rxq_info
One may need to register memory model separately from xdp_rxq_info. One
simple example may be XDP test run code, but in general, it might be
useful when memory model registering is managed by one layer and then
XDP RxQ info by a different one.
Allow such scenarios by adding a simple helper which "attaches"
already registered memory model to the desired xdp_rxq_info. As this
is mostly needed for Page Pool, add a special function to do that for
a &page_pool pointer.

Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Link: https://patch.msgid.link/20241203173733.3181246-5-aleksander.lobakin@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-12-05 18:41:06 -08:00
Taehee YooandJakub Kicinski 59a931c5b7 xdp: fix invalid wait context of page_pool_destroy()
If the driver uses a page pool, it creates a page pool with
page_pool_create().
The reference count of page pool is 1 as default.
A page pool will be destroyed only when a reference count reaches 0.
page_pool_destroy() is used to destroy page pool, it decreases a
reference count.
When a page pool is destroyed, ->disconnect() is called, which is
mem_allocator_disconnect().
This function internally acquires mutex_lock().

If the driver uses XDP, it registers a memory model with
xdp_rxq_info_reg_mem_model().
The xdp_rxq_info_reg_mem_model() internally increases a page pool
reference count if a memory model is a page pool.
Now the reference count is 2.

To destroy a page pool, the driver should call both page_pool_destroy()
and xdp_unreg_mem_model().
The xdp_unreg_mem_model() internally calls page_pool_destroy().
Only page_pool_destroy() decreases a reference count.

If a driver calls page_pool_destroy() then xdp_unreg_mem_model(), we
will face an invalid wait context warning.
Because xdp_unreg_mem_model() calls page_pool_destroy() with
rcu_read_lock().
The page_pool_destroy() internally acquires mutex_lock().

Splat looks like:
=============================
[ BUG: Invalid wait context ]
6.10.0-rc6+ #4 Tainted: G W
-----------------------------
ethtool/1806 is trying to lock:
ffffffff90387b90 (mem_id_lock){+.+.}-{4:4}, at: mem_allocator_disconnect+0x73/0x150
other info that might help us debug this:
context-{5:5}
3 locks held by ethtool/1806:
stack backtrace:
CPU: 0 PID: 1806 Comm: ethtool Tainted: G W 6.10.0-rc6+ #4 f916f41f172891c800f2fed
Hardware name: ASUS System Product Name/PRIME Z690-P D4, BIOS 0603 11/01/2021
Call Trace:
<TASK>
dump_stack_lvl+0x7e/0xc0
__lock_acquire+0x1681/0x4de0
? _printk+0x64/0xe0
? __pfx_mark_lock.part.0+0x10/0x10
? __pfx___lock_acquire+0x10/0x10
lock_acquire+0x1b3/0x580
? mem_allocator_disconnect+0x73/0x150
? __wake_up_klogd.part.0+0x16/0xc0
? __pfx_lock_acquire+0x10/0x10
? dump_stack_lvl+0x91/0xc0
__mutex_lock+0x15c/0x1690
? mem_allocator_disconnect+0x73/0x150
? __pfx_prb_read_valid+0x10/0x10
? mem_allocator_disconnect+0x73/0x150
? __pfx_llist_add_batch+0x10/0x10
? console_unlock+0x193/0x1b0
? lockdep_hardirqs_on+0xbe/0x140
? __pfx___mutex_lock+0x10/0x10
? tick_nohz_tick_stopped+0x16/0x90
? __irq_work_queue_local+0x1e5/0x330
? irq_work_queue+0x39/0x50
? __wake_up_klogd.part.0+0x79/0xc0
? mem_allocator_disconnect+0x73/0x150
mem_allocator_disconnect+0x73/0x150
? __pfx_mem_allocator_disconnect+0x10/0x10
? mark_held_locks+0xa5/0xf0
? rcu_is_watching+0x11/0xb0
page_pool_release+0x36e/0x6d0
page_pool_destroy+0xd7/0x440
xdp_unreg_mem_model+0x1a7/0x2a0
? __pfx_xdp_unreg_mem_model+0x10/0x10
? kfree+0x125/0x370
? bnxt_free_ring.isra.0+0x2eb/0x500
? bnxt_free_mem+0x5ac/0x2500
xdp_rxq_info_unreg+0x4a/0xd0
bnxt_free_mem+0x1356/0x2500
bnxt_close_nic+0xf0/0x3b0
? __pfx_bnxt_close_nic+0x10/0x10
? ethnl_parse_bit+0x2c6/0x6d0
? __pfx___nla_validate_parse+0x10/0x10
? __pfx_ethnl_parse_bit+0x10/0x10
bnxt_set_features+0x2a8/0x3e0
__netdev_update_features+0x4dc/0x1370
? ethnl_parse_bitset+0x4ff/0x750
? __pfx_ethnl_parse_bitset+0x10/0x10
? __pfx___netdev_update_features+0x10/0x10
? mark_held_locks+0xa5/0xf0
? _raw_spin_unlock_irqrestore+0x42/0x70
? __pm_runtime_resume+0x7d/0x110
ethnl_set_features+0x32d/0xa20

To fix this problem, it uses rhashtable_lookup_fast() instead of
rhashtable_lookup() with rcu_read_lock().
Using xa without rcu_read_lock() here is safe.
xa is freed by __xdp_mem_allocator_rcu_free() and this is called by
call_rcu() of mem_xa_remove().
The mem_xa_remove() is called by page_pool_destroy() if a reference
count reaches 0.
The xa is already protected by the reference count mechanism well in the
control plane.
So removing rcu_read_lock() for page_pool_destroy() is safe.

Fixes: c3f812cea0 ("page_pool: do not release pool until inflight == 0.")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Link: https://patch.msgid.link/20240712095116.3801586-1-ap420073@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-07-14 20:40:21 -07:00
Daniil DulovandDaniel Borkmann 7e9f794283 xdp: Remove WARN() from __xdp_reg_mem_model()
syzkaller reports a warning in __xdp_reg_mem_model().

The warning occurs only if __mem_id_init_hash_table() returns an error. It
returns the error in two cases:

  1. memory allocation fails;
  2. rhashtable_init() fails when some fields of rhashtable_params
     struct are not initialized properly.

The second case cannot happen since there is a static const rhashtable_params
struct with valid fields. So, warning is only triggered when there is a
problem with memory allocation.

Thus, there is no sense in using WARN() to handle this error and it can be
safely removed.

WARNING: CPU: 0 PID: 5065 at net/core/xdp.c:299 __xdp_reg_mem_model+0x2d9/0x650 net/core/xdp.c:299

CPU: 0 PID: 5065 Comm: syz-executor883 Not tainted 6.8.0-syzkaller-05271-gf99c5f563c17 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
RIP: 0010:__xdp_reg_mem_model+0x2d9/0x650 net/core/xdp.c:299

Call Trace:
 xdp_reg_mem_model+0x22/0x40 net/core/xdp.c:344
 xdp_test_run_setup net/bpf/test_run.c:188 [inline]
 bpf_test_run_xdp_live+0x365/0x1e90 net/bpf/test_run.c:377
 bpf_prog_test_run_xdp+0x813/0x11b0 net/bpf/test_run.c:1267
 bpf_prog_test_run+0x33a/0x3b0 kernel/bpf/syscall.c:4240
 __sys_bpf+0x48d/0x810 kernel/bpf/syscall.c:5649
 __do_sys_bpf kernel/bpf/syscall.c:5738 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5736 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5736
 do_syscall_64+0xfb/0x240
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

Found by Linux Verification Center (linuxtesting.org) with syzkaller.

Fixes: 8d5d885275 ("xdp: rhashtable with allocator ID to pointer mapping")
Signed-off-by: Daniil Dulov <d.dulov@aladdin.ru>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jesper Dangaard Brouer <hawk@kernel.org>
Link: https://lore.kernel.org/all/20240617162708.492159-1-d.dulov@aladdin.ru
Link: https://lore.kernel.org/bpf/20240624080747.36858-1-d.dulov@aladdin.ru
2024-06-24 13:44:02 +02:00