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Mounting btrfs from two images (which have the same one fsid and two
different dev_uuids) in certain executing order may trigger an UAF for
variable 'device->bdev_file' in __btrfs_free_extra_devids(). And
following are the details:
1. Attach image_1 to loop0, attach image_2 to loop1, and scan btrfs
devices by ioctl(BTRFS_IOC_SCAN_DEV):
/ btrfs_device_1 → loop0
fs_device
\ btrfs_device_2 → loop1
2. mount /dev/loop0 /mnt
btrfs_open_devices
btrfs_device_1->bdev_file = btrfs_get_bdev_and_sb(loop0)
btrfs_device_2->bdev_file = btrfs_get_bdev_and_sb(loop1)
btrfs_fill_super
open_ctree
fail: btrfs_close_devices // -ENOMEM
btrfs_close_bdev(btrfs_device_1)
fput(btrfs_device_1->bdev_file)
// btrfs_device_1->bdev_file is freed
btrfs_close_bdev(btrfs_device_2)
fput(btrfs_device_2->bdev_file)
3. mount /dev/loop1 /mnt
btrfs_open_devices
btrfs_get_bdev_and_sb(&bdev_file)
// EIO, btrfs_device_1->bdev_file is not assigned,
// which points to a freed memory area
btrfs_device_2->bdev_file = btrfs_get_bdev_and_sb(loop1)
btrfs_fill_super
open_ctree
btrfs_free_extra_devids
if (btrfs_device_1->bdev_file)
fput(btrfs_device_1->bdev_file) // UAF !
Fix it by setting 'device->bdev_file' as 'NULL' after closing the
btrfs_device in btrfs_close_one_device().
Fixes: 142388194191 ("btrfs: do not background blkdev_put()")
CC: stable@vger.kernel.org # 4.19+
Link: https://bugzilla.kernel.org/show_bug.cgi?id=219408
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Add a test for out-of-bounds write in trie_get_next_key() when a full
path from root to leaf exists and bpf_map_get_next_key() is called
with the leaf node. It may crashes the kernel on failure, so please
run in a VM.
Signed-off-by: Byeonguk Jeong <jungbu2855@gmail.com>
Acked-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/Zxx4ep78tsbeWPVM@localhost.localdomain
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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trie_get_next_key() allocates a node stack with size trie->max_prefixlen,
while it writes (trie->max_prefixlen + 1) nodes to the stack when it has
full paths from the root to leaves. For example, consider a trie with
max_prefixlen is 8, and the nodes with key 0x00/0, 0x00/1, 0x00/2, ...
0x00/8 inserted. Subsequent calls to trie_get_next_key with _key with
.prefixlen = 8 make 9 nodes be written on the node stack with size 8.
Fixes: b471f2f1de8b ("bpf: implement MAP_GET_NEXT_KEY command for LPM_TRIE map")
Signed-off-by: Byeonguk Jeong <jungbu2855@gmail.com>
Reviewed-by: Toke Høiland-Jørgensen <toke@kernel.org>
Tested-by: Hou Tao <houtao1@huawei.com>
Acked-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/Zxx384ZfdlFYnz6J@localhost.localdomain
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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It's only used from __io_req_set_rsrc_node(), and it takes both the ctx
and node itself, while never using the ctx. Just open-code the basic
refs++ in __io_req_set_rsrc_node() instead.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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In preparation for not pinning the whole registered file table, open
code the second potential direct file assignment. This will be handled
by appropriate helpers in the future, for now just do it manually.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Doesn't matter right now as there's still some bytes left for it, but
let's prepare for the io_kiocb potentially growing and add a specific
freeptr offset for it.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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There's no need for this internal structure to be visible, move it to
the private rsrc.h header instead.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Useful for testing performance/efficiency impact of registered files
and buffers, vs (particularly) non-registered files.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Generally applications have 1 or a few waits of waiting, yet they pass
in a struct io_uring_getevents_arg every time. This needs to get copied
and, in turn, the timeout value needs to get copied.
Rather than do this for every invocation, allow the application to
register a fixed set of wait regions that can simply be indexed when
asking the kernel to wait on events.
At ring setup time, the application can register a number of these wait
regions and initialize region/index 0 upfront:
struct io_uring_reg_wait *reg;
reg = io_uring_setup_reg_wait(ring, nr_regions, &ret);
/* set timeout and mark as set, sigmask/sigmask_sz as needed */
reg->ts.tv_sec = 0;
reg->ts.tv_nsec = 100000;
reg->flags = IORING_REG_WAIT_TS;
where nr_regions >= 1 && nr_regions <= PAGE_SIZE / sizeof(*reg). The
above initializes index 0, but 63 other regions can be initialized,
if needed. Now, instead of doing:
struct __kernel_timespec timeout = { .tv_nsec = 100000, };
io_uring_submit_and_wait_timeout(ring, &cqe, nr, &t, NULL);
to wait for events for each submit_and_wait, or just wait, operation, it
can just reference the above region at offset 0 and do:
io_uring_submit_and_wait_reg(ring, &cqe, nr, 0);
to achieve the same goal of waiting 100usec without needing to copy
both struct io_uring_getevents_arg (24b) and struct __kernel_timeout
(16b) for each invocation. Struct io_uring_reg_wait looks as follows:
struct io_uring_reg_wait {
struct __kernel_timespec ts;
__u32 min_wait_usec;
__u32 flags;
__u64 sigmask;
__u32 sigmask_sz;
__u32 pad[3];
__u64 pad2[2];
};
embedding the timeout itself in the region, rather than passing it as
a pointer as well. Note that the signal mask is still passed as a
pointer, both for compatability reasons, but also because there doesn't
seem to be a lot of high frequency waits scenarios that involve setting
and resetting the signal mask for each wait.
The application is free to modify any region before a wait call, or it
can use keep multiple regions with different settings to avoid needing to
modify the same one for wait calls. Up to a page size of regions is mapped
by default, allowing PAGE_SIZE / 64 available regions for use.
The registered region must fit within a page. On a 4kb page size system,
that allows for 64 wait regions if a full page is used, as the size of
struct io_uring_reg_wait is 64b. The region registered must be aligned
to io_uring_reg_wait in size. It's valid to register less than 64
entries.
In network performance testing with zero-copy, this reduced the time
spent waiting on the TX side from 3.12% to 0.3% and the RX side from 4.4%
to 0.3%.
Wait regions are fixed for the lifetime of the ring - once registered,
they are persistent until the ring is torn down. The regions support
minimum wait timeout as well as the regular waits.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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In scenarios where a high frequency of wait events are seen, the copy
of the struct io_uring_getevents_arg is quite noticeable in the
profiles in terms of time spent. It can be seen as up to 3.5-4.5%.
Rewrite the copy-in logic, saving about 0.5% of the time.
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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This avoids intermediate storage for turning a __kernel_timespec
user pointer into an on-stack struct timespec64, only then to turn it
into a ktime_t.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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io_sqd_handle_event() just does a mutex unlock/lock dance when it's
supposed to park, somewhat relying on full ordering with the thread
trying to park it which does a similar unlock/lock dance on sqd->lock.
However, with adaptive spinning on mutexes, this can waste an awful
lot of time. Normally this isn't very noticeable, as parking and
unparking the thread isn't a common (or fast path) occurence. However,
in testing ring resizing, it's testing exactly that, as each resize
will require the SQPOLL to safely park and unpark.
Have io_sq_thread_park() explicitly wait on sqd->park_pending being
zero before attempting to grab the sqd->lock again.
In a resize test, this brings the runtime of SQPOLL down from about
60 seconds to a few seconds, just like the !SQPOLL tests. And saves
a ton of spinning time on the mutex, on both sides.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Once a ring has been created, the size of the CQ and SQ rings are fixed.
Usually this isn't a problem on the SQ ring side, as it merely controls
the available number of requests that can be submitted in a single
system call, and there's rarely a need to change that.
For the CQ ring, it's a different story. For most efficient use of
io_uring, it's important that the CQ ring never overflows. This means
that applications must size it for the worst case scenario, which can
be wasteful.
Add IORING_REGISTER_RESIZE_RINGS, which allows an application to resize
the existing rings. It takes a struct io_uring_params argument, the same
one which is used to setup the ring initially, and resizes rings
according to the sizes given.
Certain properties are always inherited from the original ring setup,
like SQE128/CQE32 and other setup options. The implementation only
allows flag associated with how the CQ ring is sized and clamped.
Existing unconsumed SQE and CQE entries are copied as part of the
process. If either the SQ or CQ resized destination ring cannot hold the
entries already present in the source rings, then the operation is failed
with -EOVERFLOW. Any register op holds ->uring_lock, which prevents new
submissions, and the internal mapping holds the completion lock as well
across moving CQ ring state.
To prevent races between mmap and ring resizing, add a mutex that's
solely used to serialize ring resize and mmap. mmap_sem can't be used
here, as as fork'ed process may be doing mmaps on the ring as well.
The ctx->resize_lock is held across mmap operations, and the resize
will grab it before swapping out the already mapped new data.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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The later mapping will actually check this too, but in terms of code
clarify, explicitly check for whether or not the rings and sqes are
valid during validation. That makes it explicit that if they are
non-NULL, they are valid and can get mapped.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Abstract out a io_uring_fill_params() helper, which fills out the
necessary bits of struct io_uring_params. Add it to io_uring.h as well,
in preparation for having another internal user of it.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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In preparation for needing this somewhere else, move the definitions
for the maximum CQ and SQ ring size into io_uring.h. Make the
rings_size() helper available as well, and have it take just the setup
flags argument rather than the fill ring pointer. That's all that is
needed.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Put sr->umsg into a local variable, so it doesn't repeat "sr->umsg->"
for every field. It looks nicer, and likely without the patch it
compiles into a bunch of umsg memory reads.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/26c2f30b491ea7998bfdb5bb290662572a61064d.1729607201.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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We keep user pointers in an union, which could be a user buffer or a
user pointer to msghdr. What is confusing is that it potenitally reads
and assigns sqe->addr as one type but then uses it as another via the
union. Even more, it's not even consistent across copy and zerocopy
versions.
Make send and sendmsg setup helpers read sqe->addr and treat it as the
right type from the beginning. The end goal would be to get rid of
the use of struct io_sr_msg::umsg for send requests as we only need it
at the prep side.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/685d788605f5d78af18802fcabf61ba65cfd8002.1729607201.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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For non "msg" requests we copy the address at the prep stage and there
is no need to store the address user pointer long term. Pass the SQE
into io_send_setup(), let it parse it, and remove struct io_sr_msg addr
addr_len fields. It saves some space and also less confusing.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/db3dce544e17ca9d4b17d2506fbbac1da8a87824.1729607201.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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A preparation patch splitting io_sendmsg_prep_setup into two separate
helpers for send and sendmsg variants.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1a2319471ba040e053b7f1d22f4af510d1118eca.1729607201.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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It's no longer being used, remove it.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Let's keep it close with the actual import, there's no reason to do this
on the prep side. With that, we can drop one of the branches checking
for whether or not IORING_RECVSEND_FIXED_BUF is set.
As a side-effect, get rid of req->imu usage.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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All callers already hold the ring lock and hence are passing '0',
remove the argument and the conditional locking that it controlled.
Suggested-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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It's assigned in the same function that it's being used, get rid of
it. A local variable will do just fine.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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It's pretty pointless to use io_kiocb as intermediate storage for this,
so split the validity check and the actual usage. The resource node is
assigned upfront at prep time, to prevent it from going away. The actual
import is never called with the ctx->uring_lock held, so grab it for
the import.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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iter->bvec is already set to imu->bvec - remove the one dead assignment
and turn the other one into an addition instead.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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We have too many helpers posting CQEs, instead of tracing completion
events before filling in a CQE and thus having to pass all the data,
set the CQE first, pass it to the tracing helper and let it extract
everything it needs.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/b83c1ca9ee5aed2df0f3bb743bf5ed699cce4c86.1729267437.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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IORING_SETUP_NO_SQARRAY should be preferred and used by default by
liburing, optimise flag checking in io_get_sqe() with a static key.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/c164a48542fbb080115e2377ecf160c758562742.1729264988.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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io_llist_xchg is only used to set the list to NULL, which can also be
done with llist_del_all(). Use the latter and kill io_llist_xchg.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/d6765112680d2e86a58b76166b7513391ff4e5d7.1729264960.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Convert to using kvmalloc/kfree() for the hash tables, and while at it,
make it handle low memory situations better.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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All it does is initialize the lists, just move the INIT_HLIST_HEAD()
into the one caller.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Any access to the table is protected by ctx->uring_lock now anyway, the
per-bucket locking doesn't buy us anything.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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It serves no purposes anymore, all it does is delete the hash list
entry. task_work always has the ring locked.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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io_uring maintains two hash lists of inflight requests:
1) ctx->cancel_table_locked. This is used when the caller has the
ctx->uring_lock held already. This is only an issue side parameter,
as removal or task_work will always have it held.
2) ctx->cancel_table. This is used when the issuer does NOT have the
ctx->uring_lock held, and relies on the table spinlocks for access.
However, it's pretty trivial to simply grab the lock in the one spot
where we care about it, for insertion. With that, we can kill the
unlocked table (and get rid of the _locked postfix for the other one).
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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It's always req->ctx being used anyway, having this as a separate
argument (that is then not even used) just makes it more confusing.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Normally MSG_RING requires both a source and a destination ring. But
some users don't always have a ring avilable to send a message from, yet
they still need to notify a target ring.
Add support for using io_uring_register(2) without having a source ring,
using a file descriptor of -1 for that. Internally those are called
blind registration opcodes. Implement IORING_REGISTER_SEND_MSG_RING as a
blind opcode, which simply takes an sqe that the application can put on
the stack and use the normal liburing helpers to initialize it. Then the
app can call:
io_uring_register(-1, IORING_REGISTER_SEND_MSG_RING, &sqe, 1);
and get the same behavior in terms of the target, where a CQE is posted
with the details given in the sqe.
For now this takes a single sqe pointer argument, and hence arg must
be set to that, and nr_args must be 1. Could easily be extended to take
an array of sqes, but for now let's keep it simple.
Link: https://lore.kernel.org/r/20240924115932.116167-3-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Mostly just to skip them taking an io_kiocb, rather just pass in the
ctx and io_msg directly.
In preparation for being able to issue a MSG_RING request without
having an io_kiocb. No functional changes in this patch.
Link: https://lore.kernel.org/r/20240924115932.116167-2-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Everything else about the io_uring eventfd support is nicely kept
private to that code, except the cached_cq_tail tracking. With
everything else in place, move io_eventfd_flush_signal() to using
the ev_fd grab+release helpers, which then enables the direct use of
io_ev_fd for this tracking too.
Link: https://lore.kernel.org/r/20240921080307.185186-7-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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In preparation for needing the ev_fd grabbing (and releasing) from
another path, abstract out two helpers for that.
Link: https://lore.kernel.org/r/20240921080307.185186-6-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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It's a bit hard to read what guards the triggering, move it into a
helper and add a comment explaining it too. This additionally moves
the ev_fd == NULL check in there as well.
Link: https://lore.kernel.org/r/20240921080307.185186-5-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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In preparation for using this from multiple spots, move the signaling
into a helper.
Link: https://lore.kernel.org/r/20240921080307.185186-4-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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It's not necessary to do this post grabbing a reference. With that, we
can drop the out goto path as well.
Link: https://lore.kernel.org/r/20240921080307.185186-3-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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We call this in two spot, have a helper for it. In preparation for
extending this part.
Link: https://lore.kernel.org/r/20240921080307.185186-2-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Ensure the refcount and async_copies fields are initialized early.
cleanup_async_copy() will reference these fields if an error occurs
in nfsd4_copy(). If they are not correctly initialized, at the very
least, a refcount underflow occurs.
Reported-by: Olga Kornievskaia <okorniev@redhat.com>
Fixes: aadc3bbea163 ("NFSD: Limit the number of concurrent async COPY operations")
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Olga Kornievskaia <okorniev@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Merge series from Alexey Klimov <alexey.klimov@linaro.org>:
This sent as RFC because of the following:
- regarding the LO switch patch. I've got info about that from two persons
independently hence not sure what tags to put there and who should be
the author. Please let me know if that needs to be corrected.
- the wcd937x pdm watchdog is a problem for audio playback and needs to be
fixed. The minimal fix would be to at least increase timeout value but
it will still trigger in case of plenty of dbg messages or other
delay-generating things. Unfortunately, I can't test HPHL/R outputs hence
the patch is only for AUX. The other options would be introducing
module parameter for debugging and using HOLD_OFF bit for that or
adding Kconfig option.
Alexey Klimov (2):
ASoC: codecs: wcd937x: add missing LO Switch control
ASoC: codecs: wcd937x: relax the AUX PDM watchdog
sound/soc/codecs/wcd937x.c | 12 ++++++++++--
sound/soc/codecs/wcd937x.h | 4 ++++
2 files changed, 14 insertions(+), 2 deletions(-)
--
2.45.2
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Add support for Quectel RG650V which is based on Qualcomm SDX65 chip.
The composition is DIAG / NMEA / AT / AT / QMI.
T: Bus=02 Lev=01 Prnt=01 Port=03 Cnt=01 Dev#= 4 Spd=5000 MxCh= 0
D: Ver= 3.20 Cls=00(>ifc ) Sub=00 Prot=00 MxPS= 9 #Cfgs= 1
P: Vendor=2c7c ProdID=0122 Rev=05.15
S: Manufacturer=Quectel
S: Product=RG650V-EU
S: SerialNumber=xxxxxxx
C: #Ifs= 5 Cfg#= 1 Atr=a0 MxPwr=896mA
I: If#= 0 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=ff Prot=30 Driver=option
E: Ad=01(O) Atr=02(Bulk) MxPS=1024 Ivl=0ms
E: Ad=81(I) Atr=02(Bulk) MxPS=1024 Ivl=0ms
I: If#= 1 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=00 Prot=00 Driver=option
E: Ad=02(O) Atr=02(Bulk) MxPS=1024 Ivl=0ms
E: Ad=82(I) Atr=02(Bulk) MxPS=1024 Ivl=0ms
I: If#= 2 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=option
E: Ad=03(O) Atr=02(Bulk) MxPS=1024 Ivl=0ms
E: Ad=83(I) Atr=02(Bulk) MxPS=1024 Ivl=0ms
E: Ad=84(I) Atr=03(Int.) MxPS= 10 Ivl=9ms
I: If#= 3 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=option
E: Ad=04(O) Atr=02(Bulk) MxPS=1024 Ivl=0ms
E: Ad=85(I) Atr=02(Bulk) MxPS=1024 Ivl=0ms
E: Ad=86(I) Atr=03(Int.) MxPS= 10 Ivl=9ms
I: If#= 4 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=ff Prot=ff Driver=qmi_wwan
E: Ad=05(O) Atr=02(Bulk) MxPS=1024 Ivl=0ms
E: Ad=87(I) Atr=02(Bulk) MxPS=1024 Ivl=0ms
E: Ad=88(I) Atr=03(Int.) MxPS= 8 Ivl=9ms
Signed-off-by: Benoît Monin <benoit.monin@gmx.fr>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20241024151113.53203-1-benoit.monin@gmx.fr
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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This command:
$ tc qdisc replace dev eth0 ingress_block 1 egress_block 1 clsact
Error: block dev insert failed: -EBUSY.
fails because user space requests the same block index to be set for
both ingress and egress.
[ side note, I don't think it even failed prior to commit 913b47d3424e
("net/sched: Introduce tc block netdev tracking infra"), because this
is a command from an old set of notes of mine which used to work, but
alas, I did not scientifically bisect this ]
The problem is not that it fails, but rather, that the second time
around, it fails differently (and irrecoverably):
$ tc qdisc replace dev eth0 ingress_block 1 egress_block 1 clsact
Error: dsa_core: Flow block cb is busy.
[ another note: the extack is added by me for illustration purposes.
the context of the problem is that clsact_init() obtains the same
&q->ingress_block pointer as &q->egress_block, and since we call
tcf_block_get_ext() on both of them, "dev" will be added to the
block->ports xarray twice, thus failing the operation: once through
the ingress block pointer, and once again through the egress block
pointer. the problem itself is that when xa_insert() fails, we have
emitted a FLOW_BLOCK_BIND command through ndo_setup_tc(), but the
offload never sees a corresponding FLOW_BLOCK_UNBIND. ]
Even correcting the bad user input, we still cannot recover:
$ tc qdisc replace dev swp3 ingress_block 1 egress_block 2 clsact
Error: dsa_core: Flow block cb is busy.
Basically the only way to recover is to reboot the system, or unbind and
rebind the net device driver.
To fix the bug, we need to fill the correct error teardown path which
was missed during code movement, and call tcf_block_offload_unbind()
when xa_insert() fails.
[ last note, fundamentally I blame the label naming convention in
tcf_block_get_ext() for the bug. The labels should be named after what
they do, not after the error path that jumps to them. This way, it is
obviously wrong that two labels pointing to the same code mean
something is wrong, and checking the code correctness at the goto site
is also easier ]
Fixes: 94e2557d086a ("net: sched: move block device tracking into tcf_block_get/put_ext()")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Link: https://patch.msgid.link/20241023100541.974362-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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nsim_nexthop_bucket_activity_write()
This was found by a static analyzer.
We should not forget the trailing zero after copy_from_user()
if we will further do some string operations, sscanf() in this
case. Adding a trailing zero will ensure that the function
performs properly.
Fixes: c6385c0b67c5 ("netdevsim: Allow reporting activity on nexthop buckets")
Signed-off-by: Zichen Xie <zichenxie0106@gmail.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20241022171907.8606-1-zichenxie0106@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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The test added is a simplified reproducer from syzbot report [1].
If verifier does not insert checkpoint somewhere inside the loop,
verification of the program would take a very long time.
This would happen because mark_chain_precision() for register r7 would
constantly trace jump history of the loop back, processing many
iterations for each mark_chain_precision() call.
[1] https://lore.kernel.org/bpf/670429f6.050a0220.49194.0517.GAE@google.com/
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20241029172641.1042523-2-eddyz87@gmail.com
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A specifically crafted program might trick verifier into growing very
long jump history within a single bpf_verifier_state instance.
Very long jump history makes mark_chain_precision() unreasonably slow,
especially in case if verifier processes a loop.
Mitigate this by forcing new state in is_state_visited() in case if
current state's jump history is too long.
Use same constant as in `skip_inf_loop_check`, but multiply it by
arbitrarily chosen value 2 to account for jump history containing not
only information about jumps, but also information about stack access.
For an example of problematic program consider the code below,
w/o this patch the example is processed by verifier for ~15 minutes,
before failing to allocate big-enough chunk for jmp_history.
0: r7 = *(u16 *)(r1 +0);"
1: r7 += 0x1ab064b9;"
2: if r7 & 0x702000 goto 1b;
3: r7 &= 0x1ee60e;"
4: r7 += r1;"
5: if r7 s> 0x37d2 goto +0;"
6: r0 = 0;"
7: exit;"
Perf profiling shows that most of the time is spent in
mark_chain_precision() ~95%.
The easiest way to explain why this program causes problems is to
apply the following patch:
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 0c216e71cec7..4b4823961abe 100644
\--- a/include/linux/bpf.h
\+++ b/include/linux/bpf.h
\@@ -1926,7 +1926,7 @@ struct bpf_array {
};
};
-#define BPF_COMPLEXITY_LIMIT_INSNS 1000000 /* yes. 1M insns */
+#define BPF_COMPLEXITY_LIMIT_INSNS 256 /* yes. 1M insns */
#define MAX_TAIL_CALL_CNT 33
/* Maximum number of loops for bpf_loop and bpf_iter_num.
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index f514247ba8ba..75e88be3bb3e 100644
\--- a/kernel/bpf/verifier.c
\+++ b/kernel/bpf/verifier.c
\@@ -18024,8 +18024,13 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
skip_inf_loop_check:
if (!force_new_state &&
env->jmps_processed - env->prev_jmps_processed < 20 &&
- env->insn_processed - env->prev_insn_processed < 100)
+ env->insn_processed - env->prev_insn_processed < 100) {
+ verbose(env, "is_state_visited: suppressing checkpoint at %d, %d jmps processed, cur->jmp_history_cnt is %d\n",
+ env->insn_idx,
+ env->jmps_processed - env->prev_jmps_processed,
+ cur->jmp_history_cnt);
add_new_state = false;
+ }
goto miss;
}
/* If sl->state is a part of a loop and this loop's entry is a part of
\@@ -18142,6 +18147,9 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
if (!add_new_state)
return 0;
+ verbose(env, "is_state_visited: new checkpoint at %d, resetting env->jmps_processed\n",
+ env->insn_idx);
+
/* There were no equivalent states, remember the current one.
* Technically the current state is not proven to be safe yet,
* but it will either reach outer most bpf_exit (which means it's safe)
And observe verification log:
...
is_state_visited: new checkpoint at 5, resetting env->jmps_processed
5: R1=ctx() R7=ctx(...)
5: (65) if r7 s> 0x37d2 goto pc+0 ; R7=ctx(...)
6: (b7) r0 = 0 ; R0_w=0
7: (95) exit
from 5 to 6: R1=ctx() R7=ctx(...) R10=fp0
6: R1=ctx() R7=ctx(...) R10=fp0
6: (b7) r0 = 0 ; R0_w=0
7: (95) exit
is_state_visited: suppressing checkpoint at 1, 3 jmps processed, cur->jmp_history_cnt is 74
from 2 to 1: R1=ctx() R7_w=scalar(...) R10=fp0
1: R1=ctx() R7_w=scalar(...) R10=fp0
1: (07) r7 += 447767737
is_state_visited: suppressing checkpoint at 2, 3 jmps processed, cur->jmp_history_cnt is 75
2: R7_w=scalar(...)
2: (45) if r7 & 0x702000 goto pc-2
... mark_precise 152 steps for r7 ...
2: R7_w=scalar(...)
is_state_visited: suppressing checkpoint at 1, 4 jmps processed, cur->jmp_history_cnt is 75
1: (07) r7 += 447767737
is_state_visited: suppressing checkpoint at 2, 4 jmps processed, cur->jmp_history_cnt is 76
2: R7_w=scalar(...)
2: (45) if r7 & 0x702000 goto pc-2
...
BPF program is too large. Processed 257 insn
The log output shows that checkpoint at label (1) is never created,
because it is suppressed by `skip_inf_loop_check` logic:
a. When 'if' at (2) is processed it pushes a state with insn_idx (1)
onto stack and proceeds to (3);
b. At (5) checkpoint is created, and this resets
env->{jmps,insns}_processed.
c. Verification proceeds and reaches `exit`;
d. State saved at step (a) is popped from stack and is_state_visited()
considers if checkpoint needs to be added, but because
env->{jmps,insns}_processed had been just reset at step (b)
the `skip_inf_loop_check` logic forces `add_new_state` to false.
e. Verifier proceeds with current state, which slowly accumulates
more and more entries in the jump history.
The accumulation of entries in the jump history is a problem because
of two factors:
- it eventually exhausts memory available for kmalloc() allocation;
- mark_chain_precision() traverses the jump history of a state,
meaning that if `r7` is marked precise, verifier would iterate
ever growing jump history until parent state boundary is reached.
(note: the log also shows a REG INVARIANTS VIOLATION warning
upon jset processing, but that's another bug to fix).
With this patch applied, the example above is rejected by verifier
under 1s of time, reaching 1M instructions limit.
The program is a simplified reproducer from syzbot report.
Previous discussion could be found at [1].
The patch does not cause any changes in verification performance,
when tested on selftests from veristat.cfg and cilium programs taken
from [2].
[1] https://lore.kernel.org/bpf/20241009021254.2805446-1-eddyz87@gmail.com/
[2] https://github.com/anakryiko/cilium
Changelog:
- v1 -> v2:
- moved patch to bpf tree;
- moved force_new_state variable initialization after declaration and
shortened the comment.
v1: https://lore.kernel.org/bpf/20241018020307.1766906-1-eddyz87@gmail.com/
Fixes: 2589726d12a1 ("bpf: introduce bounded loops")
Reported-by: syzbot+7e46cdef14bf496a3ab4@syzkaller.appspotmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20241029172641.1042523-1-eddyz87@gmail.com
Closes: https://lore.kernel.org/bpf/670429f6.050a0220.49194.0517.GAE@google.com/
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