[ Upstream commit 7793fc3bab ]
This patch fixes an incorrect assumption made in the original
bpf_refcount series [0], specifically that the BPF program calling
bpf_refcount_acquire on some node can always guarantee that the node is
alive. In that series, the patch adding failure behavior to rbtree_add
and list_push_{front, back} breaks this assumption for non-owning
references.
Consider the following program:
n = bpf_kptr_xchg(&mapval, NULL);
/* skip error checking */
bpf_spin_lock(&l);
if(bpf_rbtree_add(&t, &n->rb, less)) {
bpf_refcount_acquire(n);
/* Failed to add, do something else with the node */
}
bpf_spin_unlock(&l);
It's incorrect to assume that bpf_refcount_acquire will always succeed in this
scenario. bpf_refcount_acquire is being called in a critical section
here, but the lock being held is associated with rbtree t, which isn't
necessarily the lock associated with the tree that the node is already
in. So after bpf_rbtree_add fails to add the node and calls bpf_obj_drop
in it, the program has no ownership of the node's lifetime. Therefore
the node's refcount can be decr'd to 0 at any time after the failing
rbtree_add. If this happens before the refcount_acquire above, the node
might be free'd, and regardless refcount_acquire will be incrementing a
0 refcount.
Later patches in the series exercise this scenario, resulting in the
expected complaint from the kernel (without this patch's changes):
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 1 PID: 207 at lib/refcount.c:25 refcount_warn_saturate+0xbc/0x110
Modules linked in: bpf_testmod(O)
CPU: 1 PID: 207 Comm: test_progs Tainted: G O 6.3.0-rc7-02231-g723de1a718a2-dirty #371
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
RIP: 0010:refcount_warn_saturate+0xbc/0x110
Code: 6f 64 f6 02 01 e8 84 a3 5c ff 0f 0b eb 9d 80 3d 5e 64 f6 02 00 75 94 48 c7 c7 e0 13 d2 82 c6 05 4e 64 f6 02 01 e8 64 a3 5c ff <0f> 0b e9 7a ff ff ff 80 3d 38 64 f6 02 00 0f 85 6d ff ff ff 48 c7
RSP: 0018:ffff88810b9179b0 EFLAGS: 00010082
RAX: 0000000000000000 RBX: 0000000000000002 RCX: 0000000000000000
RDX: 0000000000000202 RSI: 0000000000000008 RDI: ffffffff857c3680
RBP: ffff88810027d3c0 R08: ffffffff8125f2a4 R09: ffff88810b9176e7
R10: ffffed1021722edc R11: 746e756f63666572 R12: ffff88810027d388
R13: ffff88810027d3c0 R14: ffffc900005fe030 R15: ffffc900005fe048
FS: 00007fee0584a700(0000) GS:ffff88811b280000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005634a96f6c58 CR3: 0000000108ce9002 CR4: 0000000000770ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
<TASK>
bpf_refcount_acquire_impl+0xb5/0xc0
(rest of output snipped)
The patch addresses this by changing bpf_refcount_acquire_impl to use
refcount_inc_not_zero instead of refcount_inc and marking
bpf_refcount_acquire KF_RET_NULL.
For owning references, though, we know the above scenario is not possible
and thus that bpf_refcount_acquire will always succeed. Some verifier
bookkeeping is added to track "is input owning ref?" for bpf_refcount_acquire
calls and return false from is_kfunc_ret_null for bpf_refcount_acquire on
owning refs despite it being marked KF_RET_NULL.
Existing selftests using bpf_refcount_acquire are modified where
necessary to NULL-check its return value.
[0]: https://lore.kernel.org/bpf/20230415201811.343116-1-davemarchevsky@fb.com/
Fixes: d2dcc67df9 ("bpf: Migrate bpf_rbtree_add and bpf_list_push_{front,back} to possibly fail")
Reported-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230602022647.1571784-5-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit cc0d76cafe ]
Given the pointer to struct bpf_{rb,list}_node within a local kptr and
the byte offset of that field within the kptr struct, the calculation changed
by this patch is meant to find the beginning of the kptr so that it can
be passed to bpf_obj_drop.
Unfortunately instead of doing
ptr_to_kptr = ptr_to_node_field - offset_bytes
the calculation is erroneously doing
ptr_to_ktpr = ptr_to_node_field - (offset_bytes * sizeof(struct bpf_rb_node))
or the bpf_list_node equivalent.
This patch fixes the calculation.
Fixes: d2dcc67df9 ("bpf: Migrate bpf_rbtree_add and bpf_list_push_{front,back} to possibly fail")
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230602022647.1571784-4-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 2140a6e342 ]
In verifier.c, fixup_kfunc_call uses struct bpf_insn_aux_data's
kptr_struct_meta field to pass information about local kptr types to
various helpers and kfuncs at runtime. The recent bpf_refcount series
added a few functions to the set that need this information:
* bpf_refcount_acquire
* Needs to know where the refcount field is in order to increment
* Graph collection insert kfuncs: bpf_rbtree_add, bpf_list_push_{front,back}
* Were migrated to possibly fail by the bpf_refcount series. If
insert fails, the input node is bpf_obj_drop'd. bpf_obj_drop needs
the kptr_struct_meta in order to decr refcount and properly free
special fields.
Unfortunately the verifier handling of collection insert kfuncs was not
modified to actually populate kptr_struct_meta. Accordingly, when the
node input to those kfuncs is passed to bpf_obj_drop, it is done so
without the information necessary to decr refcount.
This patch fixes the issue by populating kptr_struct_meta for those
kfuncs.
Fixes: d2dcc67df9 ("bpf: Migrate bpf_rbtree_add and bpf_list_push_{front,back} to possibly fail")
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230602022647.1571784-3-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 4d585f48ee ]
For kfuncs like bpf_obj_drop and bpf_refcount_acquire - which take
user-defined types as input - the verifier needs to track the specific
type passed in when checking a particular kfunc call. This requires
tracking (btf, btf_id) tuple. In commit 7c50b1cb76
("bpf: Add bpf_refcount_acquire kfunc") I added an anonymous union with
inner structs named after the specific kfuncs tracking this information,
with the goal of making it more obvious which kfunc this data was being
tracked / expected to be tracked on behalf of.
In a recent series adding a new user of this tuple, Alexei mentioned
that he didn't like this union usage as it doesn't really help with
readability or bug-proofing ([0]). In an offline convo we agreed to
have the tuple be fields (arg_btf, arg_btf_id), with comments in
bpf_kfunc_call_arg_meta definition enumerating the uses of the fields by
kfunc-specific handling logic. Such a pattern is used by struct
bpf_reg_state without trouble.
Accordingly, this patch removes the anonymous union in favor of arg_btf
and arg_btf_id fields and comment enumerating their current uses. The
patch also removes struct btf_and_id, which was only being used by the
removed union's inner structs.
This is a mechanical change, existing linked_list and rbtree tests will
validate that correct (btf, btf_id) are being passed.
[0]: https://lore.kernel.org/bpf/20230505021707.vlyiwy57vwxglbka@dhcp-172-26-102-232.dhcp.thefacebook.com
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230510213047.1633612-1-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Stable-dep-of: 2140a6e342 ("bpf: Set kptr_struct_meta for node param to list and rbtree insert funcs")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 108598c39e ]
If it fails to attach fentry, the allocated bpf trampoline image will be
left in the system. That can be verified by checking /proc/kallsyms.
This meamleak can be verified by a simple bpf program as follows:
SEC("fentry/trap_init")
int fentry_run()
{
return 0;
}
It will fail to attach trap_init because this function is freed after
kernel init, and then we can find the trampoline image is left in the
system by checking /proc/kallsyms.
$ tail /proc/kallsyms
ffffffffc0613000 t bpf_trampoline_6442453466_1 [bpf]
ffffffffc06c3000 t bpf_trampoline_6442453466_1 [bpf]
$ bpftool btf dump file /sys/kernel/btf/vmlinux | grep "FUNC 'trap_init'"
[2522] FUNC 'trap_init' type_id=119 linkage=static
$ echo $((6442453466 & 0x7fffffff))
2522
Note that there are two left bpf trampoline images, that is because the
libbpf will fallback to raw tracepoint if -EINVAL is returned.
Fixes: e21aa34178 ("bpf: Fix fexit trampoline.")
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <song@kernel.org>
Cc: Jiri Olsa <olsajiri@gmail.com>
Link: https://lore.kernel.org/bpf/20230515130849.57502-2-laoar.shao@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 47e79cbeea ]
After commit e21aa34178 ("bpf: Fix fexit trampoline."), the selector is only
used to indicate how many times the bpf trampoline image are updated and been
displayed in the trampoline ksym name. After the trampoline is freed, the
selector will start from 0 again. So the selector is a useless value to the
user. We can remove it.
If the user want to check whether the bpf trampoline image has been updated
or not, the user can compare the address. Each time the trampoline image is
updated, the address will change consequently. Jiri also pointed out another
issue that perf is still using the old name "bpf_trampoline_%lu", so this
change can fix the issue in perf.
Fixes: e21aa34178 ("bpf: Fix fexit trampoline.")
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <song@kernel.org>
Cc: Jiri Olsa <olsajiri@gmail.com>
Link: https://lore.kernel.org/bpf/ZFvOOlrmHiY9AgXE@krava
Link: https://lore.kernel.org/bpf/20230515130849.57502-3-laoar.shao@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 29ebbba7d4 ]
With the way the hooks implemented right now, we have a special
condition: optval larger than PAGE_SIZE will expose only first 4k into
BPF; any modifications to the optval are ignored. If the BPF program
doesn't handle this condition by resetting optlen to 0,
the userspace will get EFAULT.
The intention of the EFAULT was to make it apparent to the
developers that the program is doing something wrong.
However, this inadvertently might affect production workloads
with the BPF programs that are not too careful (i.e., returning EFAULT
for perfectly valid setsockopt/getsockopt calls).
Let's try to minimize the chance of BPF program screwing up userspace
by ignoring the output of those BPF programs (instead of returning
EFAULT to the userspace). pr_info_once those cases to
the dmesg to help with figuring out what's going wrong.
Fixes: 0d01da6afc ("bpf: implement getsockopt and setsockopt hooks")
Suggested-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20230511170456.1759459-2-sdf@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit f655badf2a ]
Fix propagate_precision() logic to perform propagation of all necessary
registers and stack slots across all active frames *in one batch step*.
Doing this for each register/slot in each individual frame is wasteful,
but the main problem is that backtracking of instruction in any frame
except the deepest one just doesn't work. This is due to backtracking
logic relying on jump history, and available jump history always starts
(or ends, depending how you view it) in current frame. So, if
prog A (frame #0) called subprog B (frame #1) and we need to propagate
precision of, say, register R6 (callee-saved) within frame #0, we
actually don't even know where jump history that corresponds to prog
A even starts. We'd need to skip subprog part of jump history first to
be able to do this.
Luckily, with struct backtrack_state and __mark_chain_precision()
handling bitmasks tracking/propagation across all active frames at the
same time (added in previous patch), propagate_precision() can be both
fixed and sped up by setting all the necessary bits across all frames
and then performing one __mark_chain_precision() pass. This makes it
unnecessary to skip subprog parts of jump history.
We also improve logging along the way, to clearly specify which
registers' and slots' precision markings are propagated within which
frame. Each frame will have dedicated line and all registers and stack
slots from that frame will be reported in format similar to precision
backtrack regs/stack logging. E.g.:
frame 1: propagating r1,r2,r3,fp-8,fp-16
frame 0: propagating r3,r9,fp-120
Fixes: 529409ea92 ("bpf: propagate precision across all frames, not just the last one")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230505043317.3629845-7-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 1ef22b6865 ]
Teach __mark_chain_precision logic to maintain register/stack masks
across all active frames when going from child state to parent state.
Currently this should be mostly no-op, as precision backtracking usually
bails out when encountering subprog entry/exit.
It's not very apparent from the diff due to increased indentation, but
the logic remains the same, except everything is done on specific `fr`
frame index. Calls to bt_clear_reg() and bt_clear_slot() are replaced
with frame-specific bt_clear_frame_reg() and bt_clear_frame_slot(),
where frame index is passed explicitly, instead of using current frame
number.
We also adjust logging to emit affected frame number. And we also add
better logging of human-readable register and stack slot masks, similar
to previous patch.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230505043317.3629845-6-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Stable-dep-of: f655badf2a ("bpf: fix propagate_precision() logic for inner frames")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit d9439c21a9 ]
Add helper to format register and stack masks in more human-readable
format. Adjust logging a bit during backtrack propagation and especially
during forcing precision fallback logic to make it clearer what's going
on (with log_level=2, of course), and also start reporting affected
frame depth. This is in preparation for having more than one active
frame later when precision propagation between subprog calls is added.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230505043317.3629845-5-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Stable-dep-of: f655badf2a ("bpf: fix propagate_precision() logic for inner frames")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 407958a0e9 ]
Add struct backtrack_state and straightforward API around it to keep
track of register and stack masks used and maintained during precision
backtracking process. Having this logic separately allow to keep
high-level backtracking algorithm cleaner, but also it sets us up to
cleanly keep track of register and stack masks per frame, allowing (with
some further logic adjustments) to perform precision backpropagation
across multiple frames (i.e., subprog calls).
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230505043317.3629845-4-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Stable-dep-of: f655badf2a ("bpf: fix propagate_precision() logic for inner frames")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit ebb83d84e4 ]
After commit 8ad075c2eb ("sched: Async unthrottling for cfs
bandwidth"), we may update the rq clock multiple times in the loop of
__cfsb_csd_unthrottle().
A prior (although less common) instance of this problem exists in
unthrottle_offline_cfs_rqs().
Cure both by ensuring update_rq_clock() is called before the loop and
setting RQCF_ACT_SKIP during the loop, to supress further updates.
The alternative would be pulling update_rq_clock() out of
unthrottle_cfs_rq(), but that gives an even bigger mess.
Fixes: 8ad075c2eb ("sched: Async unthrottling for cfs bandwidth")
Reviewed-By: Ben Segall <bsegall@google.com>
Suggested-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Hao Jia <jiahao.os@bytedance.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20230613082012.49615-4-jiahao.os@bytedance.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit bf5ddd7365 ]
This code-movement-only commit moves the rcu_scale_cleanup() and
rcu_scale_shutdown() functions to follow kfree_scale_cleanup().
This is code movement is in preparation for a bug-fix patch that invokes
kfree_scale_cleanup() from rcu_scale_cleanup().
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Stable-dep-of: 23fc8df26d ("rcu/rcuscale: Stop kfree_scale_thread thread(s) after unloading rcuscale")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 401b0de3ae ]
The rcu_tasks_invoke_cbs() function relies on queue_work_on() to silently
fall back to WORK_CPU_UNBOUND when the specified CPU is offline. However,
the queue_work_on() function's silent fallback mechanism relies on that
CPU having been online at some time in the past. When queue_work_on()
is passed a CPU that has never been online, workqueue lockups ensue,
which can be bad for your kernel's general health and well-being.
This commit therefore checks whether a given CPU has ever been online,
and, if not substitutes WORK_CPU_UNBOUND in the subsequent call to
queue_work_on(). Why not simply omit the queue_work_on() call entirely?
Because this function is flooding callback-invocation notifications
to all CPUs, and must deal with possibilities that include a sparse
cpu_possible_mask.
This commit also moves the setting of the rcu_data structure's
->beenonline field to rcu_cpu_starting(), which executes on the
incoming CPU before that CPU has ever enabled interrupts. This ensures
that the required workqueues are present. In addition, because the
incoming CPU has not yet enabled its interrupts, there cannot yet have
been any softirq handlers running on this CPU, which means that the
WARN_ON_ONCE(!rdp->beenonline) within the RCU_SOFTIRQ handler cannot
have triggered yet.
Fixes: d363f833c6 ("rcu-tasks: Use workqueues for multiple rcu_tasks_invoke_cbs() invocations")
Reported-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 15d44dfa40 ]
Currently, rcu_cpu_starting() is written so that it might be invoked
with interrupts enabled. However, it is always called when interrupts
are disabled, either by rcu_init(), notify_cpu_starting(), or from a
call point prior to the call to notify_cpu_starting().
But why bother requiring that interrupts be disabled? The purpose is
to allow the rcu_data structure's ->beenonline flag to be set after all
early processing has completed for the incoming CPU, thus allowing this
flag to be used to determine when workqueues have been set up for the
incoming CPU, while still allowing this flag to be used as a diagnostic
within rcu_core().
This commit therefore makes rcu_cpu_starting() rely on interrupts being
disabled.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Stable-dep-of: 401b0de3ae ("rcu-tasks: Stop rcu_tasks_invoke_cbs() from using never-onlined CPUs")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 9d9e522010 ]
itimer_delete() has a retry loop when the timer is concurrently expired. On
non-RT kernels this just spin-waits until the timer callback has completed,
except for posix CPU timers which have HAVE_POSIX_CPU_TIMERS_TASK_WORK
enabled.
In that case and on RT kernels the existing task could live lock when
preempting the task which does the timer delivery.
Replace spin_unlock() with an invocation of timer_wait_running() to handle
it the same way as the other retry loops in the posix timer code.
Fixes: ec8f954a40 ("posix-timers: Use a callback for cancel synchronization on PREEMPT_RT")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/87v8g7c50d.ffs@tglx
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit fb49c45532 upstream.
When forking a child process, the parent write-protects anonymous pages
and COW-shares them with the child being forked using copy_present_pte().
We must not take any concurrent page faults on the source vma's as they
are being processed, as we expect both the vma and the pte's behind it
to be stable. For example, the anon_vma_fork() expects the parents
vma->anon_vma to not change during the vma copy.
A concurrent page fault on a page newly marked read-only by the page
copy might trigger wp_page_copy() and a anon_vma_prepare(vma) on the
source vma, defeating the anon_vma_clone() that wasn't done because the
parent vma originally didn't have an anon_vma, but we now might end up
copying a pte entry for a page that has one.
Before the per-vma lock based changes, the mmap_lock guaranteed
exclusion with concurrent page faults. But now we need to do a
vma_start_write() to make sure no concurrent faults happen on this vma
while it is being processed.
This fix can potentially regress some fork-heavy workloads. Kernel
build time did not show noticeable regression on a 56-core machine while
a stress test mapping 10000 VMAs and forking 5000 times in a tight loop
shows ~5% regression. If such fork time regression is unacceptable,
disabling CONFIG_PER_VMA_LOCK should restore its performance. Further
optimizations are possible if this regression proves to be problematic.
Suggested-by: David Hildenbrand <david@redhat.com>
Reported-by: Jiri Slaby <jirislaby@kernel.org>
Closes: https://lore.kernel.org/all/dbdef34c-3a07-5951-e1ae-e9c6e3cdf51b@kernel.org/
Reported-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Closes: https://lore.kernel.org/all/b198d649-f4bf-b971-31d0-e8433ec2a34c@applied-asynchrony.com/
Reported-by: Jacob Young <jacobly.alt@gmail.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217624
Fixes: 0bff0aaea0 ("x86/mm: try VMA lock-based page fault handling first")
Cc: stable@vger.kernel.org
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Dave Airlie reports that gcc-13.1.1 has started complaining about some
of the workqueue code in 32-bit arm builds:
kernel/workqueue.c: In function ‘get_work_pwq’:
kernel/workqueue.c:713:24: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
713 | return (void *)(data & WORK_STRUCT_WQ_DATA_MASK);
| ^
[ ... a couple of other cases ... ]
and while it's not immediately clear exactly why gcc started complaining
about it now, I suspect it's some C23-induced enum type handlign fixup in
gcc-13 is the cause.
Whatever the reason for starting to complain, the code and data types
are indeed disgusting enough that the complaint is warranted.
The wq code ends up creating various "helper constants" (like that
WORK_STRUCT_WQ_DATA_MASK) using an enum type, which is all kinds of
confused. The mask needs to be 'unsigned long', not some unspecified
enum type.
To make matters worse, the actual "mask and cast to a pointer" is
repeated a couple of times, and the cast isn't even always done to the
right pointer, but - as the error case above - to a 'void *' with then
the compiler finishing the job.
That's now how we roll in the kernel.
So create the masks using the proper types rather than some ambiguous
enumeration, and use a nice helper that actually does the type
conversion in one well-defined place.
Incidentally, this magically makes clang generate better code. That,
admittedly, is really just a sign of clang having been seriously
confused before, and cleaning up the typing unconfuses the compiler too.
Reported-by: Dave Airlie <airlied@gmail.com>
Link: https://lore.kernel.org/lkml/CAPM=9twNnV4zMCvrPkw3H-ajZOH-01JVh_kDrxdPYQErz8ZTdA@mail.gmail.com/
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull networking fixes from Paolo Abeni:
"Including fixes from ipsec, bpf, mptcp and netfilter.
Current release - regressions:
- netfilter: add NFT_TRANS_PREPARE_ERROR to deal with bound set/chain
- eth: mlx5e:
- fix scheduling of IPsec ASO query while in atomic
- free IRQ rmap and notifier on kernel shutdown
Current release - new code bugs:
- phy: manual remove LEDs to ensure correct ordering
Previous releases - regressions:
- mptcp: fix possible divide by zero in recvmsg()
- dsa: revert "net: phy: dp83867: perform soft reset and retain
established link"
Previous releases - always broken:
- sched: netem: acquire qdisc lock in netem_change()
- bpf:
- fix verifier id tracking of scalars on spill
- fix NULL dereference on exceptions
- accept function names that contain dots
- netfilter: disallow element updates of bound anonymous sets
- mptcp: ensure listener is unhashed before updating the sk status
- xfrm:
- add missed call to delete offloaded policies
- fix inbound ipv4/udp/esp packets to UDPv6 dualstack sockets
- selftests: fixes for FIPS mode
- dsa: mt7530: fix multiple CPU ports, BPDU and LLDP handling
- eth: sfc: use budget for TX completions
Misc:
- wifi: iwlwifi: add support for SO-F device with PCI id 0x7AF0"
* tag 'net-6.4-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (74 commits)
revert "net: align SO_RCVMARK required privileges with SO_MARK"
net: wwan: iosm: Convert single instance struct member to flexible array
sch_netem: acquire qdisc lock in netem_change()
selftests: forwarding: Fix race condition in mirror installation
wifi: mac80211: report all unusable beacon frames
mptcp: ensure listener is unhashed before updating the sk status
mptcp: drop legacy code around RX EOF
mptcp: consolidate fallback and non fallback state machine
mptcp: fix possible list corruption on passive MPJ
mptcp: fix possible divide by zero in recvmsg()
mptcp: handle correctly disconnect() failures
bpf: Force kprobe multi expected_attach_type for kprobe_multi link
bpf/btf: Accept function names that contain dots
Revert "net: phy: dp83867: perform soft reset and retain established link"
net: mdio: fix the wrong parameters
netfilter: nf_tables: Fix for deleting base chains with payload
netfilter: nfnetlink_osf: fix module autoload
netfilter: nf_tables: drop module reference after updating chain
netfilter: nf_tables: disallow timeout for anonymous sets
netfilter: nf_tables: disallow updates of anonymous sets
...
Pull cgroup fixes from Tejun Heo:
"It's late but here are two bug fixes. Both fix problems which can be
severe but are very confined in scope. The risk to most use cases
should be minimal.
- Fix for an old bug which triggers if a cgroup subsystem is
remounted to a different hierarchy while someone is reading its
cgroup.procs/tasks file. The risk is pretty low given how seldom
cgroup subsystems are moved across hierarchies.
- We moved cpus_read_lock() outside of cgroup internal locks a while
ago but forgot to update the legacy_freezer leading to lockdep
triggers. Fixed"
* tag 'cgroup-for-6.4-rc7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: Do not corrupt task iteration when rebinding subsystem
cgroup,freezer: hold cpu_hotplug_lock before freezer_mutex in freezer_css_{online,offline}()
Daniel Borkmann says:
====================
pull-request: bpf 2023-06-21
We've added 7 non-merge commits during the last 14 day(s) which contain
a total of 7 files changed, 181 insertions(+), 15 deletions(-).
The main changes are:
1) Fix a verifier id tracking issue with scalars upon spill,
from Maxim Mikityanskiy.
2) Fix NULL dereference if an exception is generated while a BPF
subprogram is running, from Krister Johansen.
3) Fix a BTF verification failure when compiling kernel with LLVM_IAS=0,
from Florent Revest.
4) Fix expected_attach_type enforcement for kprobe_multi link,
from Jiri Olsa.
5) Fix a bpf_jit_dump issue for x86_64 to pick the correct JITed image,
from Yonghong Song.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
bpf: Force kprobe multi expected_attach_type for kprobe_multi link
bpf/btf: Accept function names that contain dots
selftests/bpf: add a test for subprogram extables
bpf: ensure main program has an extable
bpf: Fix a bpf_jit_dump issue for x86_64 with sysctl bpf_jit_enable.
selftests/bpf: Add test cases to assert proper ID tracking on spill
bpf: Fix verifier id tracking of scalars on spill
====================
Link: https://lore.kernel.org/r/20230621101116.16122-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Pull timer fix from Thomas Gleixner:
"A single regression fix for a regression fix:
For a long time the tick was aligned to clock MONOTONIC so that the
tick event happened at a multiple of nanoseconds per tick starting
from clock MONOTONIC = 0.
At some point this changed as the refined jiffies clocksource which is
used during boot before the TSC or other clocksources becomes usable,
was adjusted with a boot offset, so that time 0 is closer to the point
where the kernel starts.
This broke the assumption in the tick code that when the tick setup
happens early on ktime_get() will return a multiple of nanoseconds per
tick. As a consequence applications which aligned their periodic
execution so that it does not collide with the tick were not longer
guaranteed that the tick period starts from time 0.
The fix for this regression was to realign the tick when it is
initially set up to a multiple of tick periods. That works as long as
the underlying tick device supports periodic mode, but breaks under
certain conditions when the tick device supports only one shot mode.
Depending on the offset, the alignment delta to clock MONOTONIC can
get in a range where the minimal programming delta of the underlying
clock event device is larger than the calculated delta to the next
tick. This results in a boot hang as the tick code tries to play catch
up, but as the tick never fires jiffies are not advanced so it keeps
trying for ever.
Solve this by moving the tick alignement into the NOHZ / HIGHRES
enablement code because at that point it is guaranteed that the
underlying clocksource is high resolution capable and not longer
depending on the tick.
This is far before user space starts, so at the point where
applications try to align their timers, the old behaviour of the tick
happening at a multiple of nanoseconds per tick starting from clock
MONOTONIC = 0 is restored"
* tag 'timers-urgent-2023-06-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
tick/common: Align tick period during sched_timer setup
We currently allow to create perf link for program with
expected_attach_type == BPF_TRACE_KPROBE_MULTI.
This will cause crash when we call helpers like get_attach_cookie or
get_func_ip in such program, because it will call the kprobe_multi's
version (current->bpf_ctx context setup) of those helpers while it
expects perf_link's current->bpf_ctx context setup.
Making sure that we use BPF_TRACE_KPROBE_MULTI expected_attach_type
only for programs attaching through kprobe_multi link.
Fixes: ca74823c6e ("bpf: Add cookie support to programs attached with kprobe multi link")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20230618131414.75649-1-jolsa@kernel.org
When building a kernel with LLVM=1, LLVM_IAS=0 and CONFIG_KASAN=y, LLVM
leaves DWARF tags for the "asan.module_ctor" & co symbols. In turn,
pahole creates BTF_KIND_FUNC entries for these and this makes the BTF
metadata validation fail because they contain a dot.
In a dramatic turn of event, this BTF verification failure can cause
the netfilter_bpf initialization to fail, causing netfilter_core to
free the netfilter_helper hashmap and netfilter_ftp to trigger a
use-after-free. The risk of u-a-f in netfilter will be addressed
separately but the existence of "asan.module_ctor" debug info under some
build conditions sounds like a good enough reason to accept functions
that contain dots in BTF.
Although using only LLVM=1 is the recommended way to compile clang-based
kernels, users can certainly do LLVM=1, LLVM_IAS=0 as well and we still
try to support that combination according to Nick. To clarify:
- > v5.10 kernel, LLVM=1 (LLVM_IAS=0 is not the default) is recommended,
but user can still have LLVM=1, LLVM_IAS=0 to trigger the issue
- <= 5.10 kernel, LLVM=1 (LLVM_IAS=0 is the default) is recommended in
which case GNU as will be used
Fixes: 1dc9285184 ("bpf: kernel side support for BTF Var and DataSec")
Signed-off-by: Florent Revest <revest@chromium.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Cc: Yonghong Song <yhs@meta.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/bpf/20230615145607.3469985-1-revest@chromium.org
Pull tracing fixes from Steven Rostedt:
- Fix MAINTAINERS file to point to proper mailing list for rtla and rv
The mailing list pointed to linux-trace-devel instead of
linux-trace-kernel. The former is for the tracing libraries and the
latter is for anything in the Linux kernel tree. The wrong mailing
list was used because linux-trace-kernel did not exist when rtla and
rv were created.
- User events:
- Fix matching of dynamic events to their user events
When user writes to dynamic_events file, a lookup of the
registered dynamic events is made, but there were some cases that
a match could be incorrectly made.
- Add auto cleanup of user events
Have the user events automatically get removed when the last
reference (file descriptor) is closed. This was asked for to
prevent leaks of user events hanging around needing admins to
clean them up.
- Add persistent logic (but not let user space use it yet)
In some cases, having a persistent user event (one that does not
get cleaned up automatically) is useful. But there's still debates
about how to expose this to user space. The infrastructure is
added, but the API is not.
- Update the selftests
Update the user event selftests to reflect the above changes"
* tag 'trace-v6.4-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing/user_events: Document auto-cleanup and remove dyn_event refs
selftests/user_events: Adapt dyn_test to non-persist events
selftests/user_events: Ensure auto cleanup works as expected
tracing/user_events: Add auto cleanup and future persist flag
tracing/user_events: Track refcount consistently via put/get
tracing/user_events: Store register flags on events
tracing/user_events: Remove user_ns walk for groups
selftests/user_events: Add perf self-test for empty arguments events
selftests/user_events: Clear the events after perf self-test
selftests/user_events: Add ftrace self-test for empty arguments events
tracing/user_events: Fix the incorrect trace record for empty arguments events
tracing: Modify print_fields() for fields output order
tracing/user_events: Handle matching arguments that is null from dyn_events
tracing/user_events: Prevent same name but different args event
tracing/rv/rtla: Update MAINTAINERS file to point to proper mailing list
The tick period is aligned very early while the first clock_event_device is
registered. At that point the system runs in periodic mode and switches
later to one-shot mode if possible.
The next wake-up event is programmed based on the aligned value
(tick_next_period) but the delta value, that is used to program the
clock_event_device, is computed based on ktime_get().
With the subtracted offset, the device fires earlier than the exact time
frame. With a large enough offset the system programs the timer for the
next wake-up and the remaining time left is too small to make any boot
progress. The system hangs.
Move the alignment later to the setup of tick_sched timer. At this point
the system switches to oneshot mode and a high resolution clocksource is
available. At this point it is safe to align tick_next_period because
ktime_get() will now return accurate (not jiffies based) time.
[bigeasy: Patch description + testing].
Fixes: e9523a0d81 ("tick/common: Align tick period with the HZ tick.")
Reported-by: Mathias Krause <minipli@grsecurity.net>
Reported-by: "Bhatnagar, Rishabh" <risbhat@amazon.com>
Suggested-by: Mathias Krause <minipli@grsecurity.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
Tested-by: Mathias Krause <minipli@grsecurity.net>
Acked-by: SeongJae Park <sj@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/5a56290d-806e-b9a5-f37c-f21958b5a8c0@grsecurity.net
Link: https://lore.kernel.org/12c6f9a3-d087-b824-0d05-0d18c9bc1bf3@amazon.com
Link: https://lore.kernel.org/r/20230615091830.RxMV2xf_@linutronix.de
Currently user events need to be manually deleted via the delete IOCTL
call or via the dynamic_events file. Most operators and processes wish
to have these events auto cleanup when they are no longer used by
anything to prevent them piling without manual maintenance. However,
some operators may not want this, such as pre-registering events via the
dynamic_events tracefs file.
Update user_event_put() to attempt an auto delete of the event if it's
the last reference. The auto delete must run in a work queue to ensure
proper behavior of class->reg() invocations that don't expect the call
to go away from underneath them during the unregister. Add work_struct
to user_event struct to ensure we can do this reliably.
Add a persist flag, that is not yet exposed, to ensure we can toggle
between auto-cleanup and leaving the events existing in the future. When
a non-zero flag is seen during register, return -EINVAL to ensure ABI
is clear for the user processes while we work out the best approach for
persistent events.
Link: https://lkml.kernel.org/r/20230614163336.5797-4-beaub@linux.microsoft.com
Link: https://lore.kernel.org/linux-trace-kernel/20230518093600.3f119d68@rorschach.local.home/
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Various parts of the code today track user_event's refcnt field directly
via a refcount_add/dec. This makes it hard to modify the behavior of the
last reference decrement in all code paths consistently. For example, in
the future we will auto-delete events upon the last reference going
away. This last reference could happen in many places, but we want it to
be consistently handled.
Add user_event_get() and user_event_put() for the add/dec. Update all
places where direct refcounts are being used to utilize these new
functions. In each location pass if event_mutex is locked or not. This
allows us to drop events automatically in future patches clearly. Ensure
when caller states the lock is held, it really is (or is not) held.
Link: https://lkml.kernel.org/r/20230614163336.5797-3-beaub@linux.microsoft.com
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Currently we don't have any available flags for user processes to use to
indicate options for user_events. We will soon have a flag to indicate
the event should or should not auto-delete once it's not being used by
anyone.
Add a reg_flags field to user_events and parameters to existing
functions to allow for this in future patches.
Link: https://lkml.kernel.org/r/20230614163336.5797-2-beaub@linux.microsoft.com
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
When subprograms are in use, the main program is not jit'd after the
subprograms because jit_subprogs sets a value for prog->bpf_func upon
success. Subsequent calls to the JIT are bypassed when this value is
non-NULL. This leads to a situation where the main program and its
func[0] counterpart are both in the bpf kallsyms tree, but only func[0]
has an extable. Extables are only created during JIT. Now there are
two nearly identical program ksym entries in the tree, but only one has
an extable. Depending upon how the entries are placed, there's a chance
that a fault will call search_extable on the aux with the NULL entry.
Since jit_subprogs already copies state from func[0] to the main
program, include the extable pointer in this state duplication.
Additionally, ensure that the copy of the main program in func[0] is not
added to the bpf_prog_kallsyms table. Instead, let the main program get
added later in bpf_prog_load(). This ensures there is only a single
copy of the main program in the kallsyms table, and that its tag matches
the tag observed by tooling like bpftool.
Cc: stable@vger.kernel.org
Fixes: 1c2a088a66 ("bpf: x64: add JIT support for multi-function programs")
Signed-off-by: Krister Johansen <kjlx@templeofstupid.com>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/r/6de9b2f4b4724ef56efbb0339daaa66c8b68b1e7.1686616663.git.kjlx@templeofstupid.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Pull misc fixes from Andrew Morton:
"19 hotfixes. 14 are cc:stable and the remainder address issues which
were introduced during this development cycle or which were considered
inappropriate for a backport"
* tag 'mm-hotfixes-stable-2023-06-12-12-22' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
zswap: do not shrink if cgroup may not zswap
page cache: fix page_cache_next/prev_miss off by one
ocfs2: check new file size on fallocate call
mailmap: add entry for John Keeping
mm/damon/core: fix divide error in damon_nr_accesses_to_accesses_bp()
epoll: ep_autoremove_wake_function should use list_del_init_careful
mm/gup_test: fix ioctl fail for compat task
nilfs2: reject devices with insufficient block count
ocfs2: fix use-after-free when unmounting read-only filesystem
lib/test_vmalloc.c: avoid garbage in page array
nilfs2: fix possible out-of-bounds segment allocation in resize ioctl
riscv/purgatory: remove PGO flags
powerpc/purgatory: remove PGO flags
x86/purgatory: remove PGO flags
kexec: support purgatories with .text.hot sections
mm/uffd: allow vma to merge as much as possible
mm/uffd: fix vma operation where start addr cuts part of vma
radix-tree: move declarations to header
nilfs2: fix incomplete buffer cleanup in nilfs_btnode_abort_change_key()
We found a refcount UAF bug as follows:
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 1 PID: 342 at lib/refcount.c:25 refcount_warn_saturate+0xa0/0x148
Workqueue: events cpuset_hotplug_workfn
Call trace:
refcount_warn_saturate+0xa0/0x148
__refcount_add.constprop.0+0x5c/0x80
css_task_iter_advance_css_set+0xd8/0x210
css_task_iter_advance+0xa8/0x120
css_task_iter_next+0x94/0x158
update_tasks_root_domain+0x58/0x98
rebuild_root_domains+0xa0/0x1b0
rebuild_sched_domains_locked+0x144/0x188
cpuset_hotplug_workfn+0x138/0x5a0
process_one_work+0x1e8/0x448
worker_thread+0x228/0x3e0
kthread+0xe0/0xf0
ret_from_fork+0x10/0x20
then a kernel panic will be triggered as below:
Unable to handle kernel paging request at virtual address 00000000c0000010
Call trace:
cgroup_apply_control_disable+0xa4/0x16c
rebind_subsystems+0x224/0x590
cgroup_destroy_root+0x64/0x2e0
css_free_rwork_fn+0x198/0x2a0
process_one_work+0x1d4/0x4bc
worker_thread+0x158/0x410
kthread+0x108/0x13c
ret_from_fork+0x10/0x18
The race that cause this bug can be shown as below:
(hotplug cpu) | (umount cpuset)
mutex_lock(&cpuset_mutex) | mutex_lock(&cgroup_mutex)
cpuset_hotplug_workfn |
rebuild_root_domains | rebind_subsystems
update_tasks_root_domain | spin_lock_irq(&css_set_lock)
css_task_iter_start | list_move_tail(&cset->e_cset_node[ss->id]
while(css_task_iter_next) | &dcgrp->e_csets[ss->id]);
css_task_iter_end | spin_unlock_irq(&css_set_lock)
mutex_unlock(&cpuset_mutex) | mutex_unlock(&cgroup_mutex)
Inside css_task_iter_start/next/end, css_set_lock is hold and then
released, so when iterating task(left side), the css_set may be moved to
another list(right side), then it->cset_head points to the old list head
and it->cset_pos->next points to the head node of new list, which can't
be used as struct css_set.
To fix this issue, switch from all css_sets to only scgrp's css_sets to
patch in-flight iterators to preserve correct iteration, and then
update it->cset_head as well.
Reported-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Link: https://www.spinics.net/lists/cgroups/msg37935.html
Suggested-by: Michal Koutný <mkoutny@suse.com>
Link: https://lore.kernel.org/all/20230526114139.70274-1-xiujianfeng@huaweicloud.com/
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Fixes: 2d8f243a5e ("cgroup: implement cgroup->e_csets[]")
Cc: stable@vger.kernel.org # v3.16+
Signed-off-by: Tejun Heo <tj@kernel.org>
Pull virtio bug fixes from Michael Tsirkin:
"A bunch of fixes all over the place"
* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
tools/virtio: use canonical ftrace path
vhost_vdpa: support PACKED when setting-getting vring_base
vhost: support PACKED when setting-getting vring_base
vhost: Fix worker hangs due to missed wake up calls
vhost: Fix crash during early vhost_transport_send_pkt calls
vhost_net: revert upend_idx only on retriable error
vhost_vdpa: tell vqs about the negotiated
vdpa/mlx5: Fix hang when cvq commands are triggered during device unregister
tools/virtio: Add .gitignore for ringtest
tools/virtio: Fix arm64 ringtest compilation error
vduse: avoid empty string for dev name
vhost: use kzalloc() instead of kmalloc() followed by memset()
Pull cgroup fixes from Tejun Heo:
- Fix css_set reference leaks on fork failures
- Fix CPU hotplug locking in cgroup_transfer_tasks() which is used by
cgroup1 cpuset
- Doc update
* tag 'cgroup-for-6.4-rc5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: Documentation: Clarify usage of memory limits
cgroup: always put cset in cgroup_css_set_put_fork
cgroup: fix missing cpus_read_{lock,unlock}() in cgroup_transfer_tasks()
We can race where we have added work to the work_list, but
vhost_task_fn has passed that check but not yet set us into
TASK_INTERRUPTIBLE. wake_up_process will see us in TASK_RUNNING and
just return.
This bug was intoduced in commit f9010dbdce ("fork, vhost: Use
CLONE_THREAD to fix freezer/ps regression") when I moved the setting
of TASK_INTERRUPTIBLE to simplfy the code and avoid get_signal from
logging warnings about being in the wrong state. This moves the setting
of TASK_INTERRUPTIBLE back to before we test if we need to stop the
task to avoid a possible race there as well. We then have vhost_worker
set TASK_RUNNING if it finds work similar to before.
Fixes: f9010dbdce ("fork, vhost: Use CLONE_THREAD to fix freezer/ps regression")
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Message-Id: <20230607192338.6041-3-michael.christie@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
The following scenario describes a bug in the verifier where it
incorrectly concludes about equivalent scalar IDs which could lead to
verifier bypass in privileged mode:
1. Prepare a 32-bit rogue number.
2. Put the rogue number into the upper half of a 64-bit register, and
roll a random (unknown to the verifier) bit in the lower half. The
rest of the bits should be zero (although variations are possible).
3. Assign an ID to the register by MOVing it to another arbitrary
register.
4. Perform a 32-bit spill of the register, then perform a 32-bit fill to
another register. Due to a bug in the verifier, the ID will be
preserved, although the new register will contain only the lower 32
bits, i.e. all zeros except one random bit.
At this point there are two registers with different values but the same
ID, which means the integrity of the verifier state has been corrupted.
5. Compare the new 32-bit register with 0. In the branch where it's
equal to 0, the verifier will believe that the original 64-bit
register is also 0, because it has the same ID, but its actual value
still contains the rogue number in the upper half.
Some optimizations of the verifier prevent the actual bypass, so
extra care is needed: the comparison must be between two registers,
and both branches must be reachable (this is why one random bit is
needed). Both branches are still suitable for the bypass.
6. Right shift the original register by 32 bits to pop the rogue number.
7. Use the rogue number as an offset with any pointer. The verifier will
believe that the offset is 0, while in reality it's the given number.
The fix is similar to the 32-bit BPF_MOV handling in check_alu_op for
SCALAR_VALUE. If the spill is narrowing the actual register value, don't
keep the ID, make sure it's reset to 0.
Fixes: 354e8f1970 ("bpf: Support <8-byte scalar spill and refill")
Signed-off-by: Maxim Mikityanskiy <maxim@isovalent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Andrii Nakryiko <andrii@kernel.org> # Checked veristat delta
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20230607123951.558971-2-maxtram95@gmail.com
Daniel Borkmann says:
====================
pull-request: bpf 2023-06-07
We've added 7 non-merge commits during the last 7 day(s) which contain
a total of 12 files changed, 112 insertions(+), 7 deletions(-).
The main changes are:
1) Fix a use-after-free in BPF's task local storage, from KP Singh.
2) Make struct path handling more robust in bpf_d_path, from Jiri Olsa.
3) Fix a syzbot NULL-pointer dereference in sockmap, from Eric Dumazet.
4) UAPI fix for BPF_NETFILTER before final kernel ships,
from Florian Westphal.
5) Fix map-in-map array_map_gen_lookup code generation where elem_size was
not being set for inner maps, from Rhys Rustad-Elliott.
6) Fix sockopt_sk selftest's NETLINK_LIST_MEMBERSHIPS assertion,
from Yonghong Song.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
bpf: Add extra path pointer check to d_path helper
selftests/bpf: Fix sockopt_sk selftest
bpf: netfilter: Add BPF_NETFILTER bpf_attach_type
selftests/bpf: Add access_inner_map selftest
bpf: Fix elem_size not being set for inner maps
bpf: Fix UAF in task local storage
bpf, sockmap: Avoid potential NULL dereference in sk_psock_verdict_data_ready()
====================
Link: https://lore.kernel.org/r/20230607220514.29698-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Anastasios reported crash on stable 5.15 kernel with following
BPF attached to lsm hook:
SEC("lsm.s/bprm_creds_for_exec")
int BPF_PROG(bprm_creds_for_exec, struct linux_binprm *bprm)
{
struct path *path = &bprm->executable->f_path;
char p[128] = { 0 };
bpf_d_path(path, p, 128);
return 0;
}
But bprm->executable can be NULL, so bpf_d_path call will crash:
BUG: kernel NULL pointer dereference, address: 0000000000000018
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC NOPTI
...
RIP: 0010:d_path+0x22/0x280
...
Call Trace:
<TASK>
bpf_d_path+0x21/0x60
bpf_prog_db9cf176e84498d9_bprm_creds_for_exec+0x94/0x99
bpf_trampoline_6442506293_0+0x55/0x1000
bpf_lsm_bprm_creds_for_exec+0x5/0x10
security_bprm_creds_for_exec+0x29/0x40
bprm_execve+0x1c1/0x900
do_execveat_common.isra.0+0x1af/0x260
__x64_sys_execve+0x32/0x40
It's problem for all stable trees with bpf_d_path helper, which was
added in 5.9.
This issue is fixed in current bpf code, where we identify and mark
trusted pointers, so the above code would fail even to load.
For the sake of the stable trees and to workaround potentially broken
verifier in the future, adding the code that reads the path object from
the passed pointer and verifies it's valid in kernel space.
Fixes: 6e22ab9da7 ("bpf: Add d_path helper")
Reported-by: Anastasios Papagiannis <tasos.papagiannnis@gmail.com>
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20230606181714.532998-1-jolsa@kernel.org
Andrii Nakryiko writes:
And we currently don't have an attach type for NETLINK BPF link.
Thankfully it's not too late to add it. I see that link_create() in
kernel/bpf/syscall.c just bypasses attach_type check. We shouldn't
have done that. Instead we need to add BPF_NETLINK attach type to enum
bpf_attach_type. And wire all that properly throughout the kernel and
libbpf itself.
This adds BPF_NETFILTER and uses it. This breaks uabi but this
wasn't in any non-rc release yet, so it should be fine.
v2: check link_attack prog type in link_create too
Fixes: 84601d6ee6 ("bpf: add bpf_link support for BPF_NETFILTER programs")
Suggested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/CAEf4BzZ69YgrQW7DHCJUT_X+GqMq_ZQQPBwopaJJVGFD5=d5Vg@mail.gmail.com/
Link: https://lore.kernel.org/bpf/20230605131445.32016-1-fw@strlen.de
Pull probes fixes from Masami Hiramatsu:
- Return NULL if the trace_probe list on trace_probe_event is empty
- selftests/ftrace: Choose testing symbol name for filtering feature
from sample data instead of fixed symbol
* tag 'probes-fixes-6.4-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
selftests/ftrace: Choose target function for filter test from samples
tracing/probe: trace_probe_primary_from_call(): checked list_first_entry
