| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
rust_binder: reschedule node refcount update on thread exit
When a thread exits via BINDER_THREAD_EXIT, its pending work items are
cancelled. If a thread exits while holding a pending node refcount
increment (e.g. pushed as deferred work to that thread), the refcount
increment was previously dropped because Node::cancel() and
NodeWrapper::cancel() were no-ops.
Dropping the refcount update leaves the node's delivery state and count
state desynchronized, and userspace will not receive the notification,
which can cause the node to never be freed from the process's nodes tree
when all external references are dropped.
Fix this by implementing DeliverToRead::cancel() for Node and NodeWrapper
to move the pending refcount update to the process's work queue on thread
exit so another thread can deliver it to userspace. |
| In the Linux kernel, the following vulnerability has been resolved:
fs: Free any excess xarray nodes in clear_inode()
For many years we've had a hard to hit leak of xarray nodes. Hugh
documented it well in commit 786b31121a2c. Recently people and
syzbot have found ways to force it to happen with madvise. Rather
than fix the leaks where they happen, just call xa_destroy() which
has the side-effect of cycling the i_pages lock. |
| In the Linux kernel, the following vulnerability has been resolved:
isofs: handle set_blocksize failures
isofs uses buffer_heads, which don't handle block size > PAGE_SIZE well.
Without this, mounting we will hit the
BUG_ON(offset >= folio_size(folio));
in folio_set_bh on the first __bread_gfp call. |
| In the Linux kernel, the following vulnerability has been resolved:
mm/damon/ops-common: use a page-aligned address in damon_ptep_mkold()
__damon_va_prepare_access_check() picks a random byte address within the
region and stores it in r->sampling_addr. damon_va_mkold() passes it into
a page table walk, which hands it to damon_ptep_mkold() as the address of
the page to sample:
damon_va_mkold(mm, r->sampling_addr)
damon_va_walk_page_range(mm, addr, addr + 1)
damon_mkold_pmd_entry()
damon_ptep_mkold(pte, vma, addr)
ptep_test_and_clear_young(vma, addr, pte)
mmu_notifier_clear_young(mm, addr, addr + PAGE_SIZE)
For arm64, before commit 6f0e1142173a ("arm64: mm: support batch clearing
of the young flag for large folios"), the contpte helper walked exactly
CONT_PTES entries from the aligned-down page table pointer and used @addr
only to pass down to each entry, so an unaligned value was harmless:
ptep = contpte_align_down(ptep);
addr = ALIGN_DOWN(addr, CONT_PTE_SIZE);
for (i = 0; i < CONT_PTES; i++, ptep++, addr += PAGE_SIZE)
Now the range to walk is derived from @addr instead: end = addr + nr *
PAGE_SIZE, rounded up to CONT_PTE_SIZE. For a sample in the last page of
a contpte block, the sub-page offset puts end just past the block
boundary, so the round-up lands a whole block further and the walk clears
PTE_AF in CONT_PTES entries beyond the sampled block. For the last block
in a page table page, those entries are past the end of that page, so the
walk writes into the page that follows.
Triggered by the full 7.1/7.2 kernel selftest suite on arm64 (EC2
c/m6g.4xlarge). The kernel sometimes crashes at or shortly after the
DAMON test.
What the overrun does depends on the page that happens to follow the page
table, so there is no single signature. If that page is read-only, the
write faults in the sampling path itself:
Unable to handle kernel write to read-only memory at virtual address ffff0003c5d2d000
FSC = 0x0f: level 3 permission fault
CM = 0, WnR = 1, TnD = 0, TagAccess = 0
CPU: 10 UID: 0 PID: 3487 Comm: kdamond.2
pc : contpte_test_and_clear_young_ptes+0x70/0xc0
lr : damon_ptep_mkold+0x1e8/0x1f8
Call trace:
contpte_test_and_clear_young_ptes+0x70/0xc0 (P)
damon_mkold_pmd_entry+0x150/0x170
walk_pmd_range+0x110/0x2b0
walk_pud_range+0x10c/0x208
walk_pgd_range+0x134/0x258
__walk_page_range+0x98/0x1b0
walk_page_range_vma_unsafe+0x90/0x148
walk_page_range_vma+0x28/0x40
damon_va_walk_page_range+0x114/0x2b8
damon_va_prepare_access_checks+0xec/0x1a8
kdamond_fn+0x534/0x770
kthread+0x128/0x138
ret_from_fork+0x10/0x20
Otherwise the page is writable, the PTE_AF clearing succeeds silently and
the damage only surfaces later, in whatever happened to own the page, so
the backtrace is unrelated to DAMON and differs between runs.
Pass a page-aligned address to the ptep_test_and_clear_young() call in
damon_ptep_mkold(), which is the only place DAMON can reach
contpte_test_and_clear_young_ptes() from. Nothing else sees the aligned
address, and r->sampling_addr itself is left as is, so the sampling and
region bookkeeping semantics are unchanged. |
| In the Linux kernel, the following vulnerability has been resolved:
usb: hub: use shorter 120ms post resume hold for SS root hubs
Holding a USB3 hub PM runtime reference for 200ms at hub resume triggers
an AMD platform issue. Users running Android adb report crashes after
adb has been polling and waking up the USB subsystem once a second for
some time. Vendors are working on a solution. Disabling USB runtime PM
is one way to prevent this issue, but it is also proven that reducing the
hold time to 120ms in resume also mitigates it. See Link for more
details.
Reducing the hold time to 120ms for the USB3 roothub is in itself a valid
change and optimization, as the current 200ms is excessive: a root hub
has no upstream suspended hub whose wake propagation needs to be
accounted for, but still need some time for USB3 link training to
complete.
Keep the 200ms hold for external hubs that commit 8f5b7e2bec1c
("usb: hub: fix detection of high tier USB3 devices behind suspended
hubs") is intended for. |
| In the Linux kernel, the following vulnerability has been resolved:
ipv6: sr: use skb_get_hash_net() in seg6_make_flowlabel()
Since commit d58e468b1112 ("flow_dissector: implements flow dissector
BPF hook") __skb_flow_dissect() needs a net pointer, either from
skb->dev, skb->sk, or since commit 3cbf4ffba5ee ("net: plumb network
namespace into __skb_flow_dissect") a caller provided pointer.
syzbot was able to reach seg6_make_flowlabel() with an skb having
neither skb->dev nor skb->sk set: a TIPC UDP bearer sends a discovery
message through an IPv4 route using seg6 encap, while
net.ipv6.seg6_flowlabel is set to 1.
seg6_make_flowlabel() already has a net pointer, use skb_get_hash_net().
WARNING: net/core/flow_dissector.c:1131 at __skb_flow_dissect+0x910/0x5368 net/core/flow_dissector.c:1126, CPU#0: syz.0.17/4930
Call trace:
__skb_flow_dissect+0x910/0x5368 net/core/flow_dissector.c:1126 (P)
__skb_get_hash_net+0xe0/0x29c net/core/flow_dissector.c:1903
skb_get_hash include/linux/skbuff.h:1663 [inline]
seg6_make_flowlabel+0xcc/0x1ec net/ipv6/seg6_iptunnel.c:132
__seg6_do_srh_encap+0x320/0xbf4 net/ipv6/seg6_iptunnel.c:161
seg6_do_srh+0x4b4/0xa44 net/ipv6/seg6_iptunnel.c:431
seg6_output_core+0x164/0x688 net/ipv6/seg6_iptunnel.c:681
seg6_output+0x44/0x1ac net/ipv6/seg6_iptunnel.c:744
lwtunnel_output+0x3d0/0x664 net/core/lwtunnel.c:356
dst_output include/net/dst.h:470 [inline]
ip_local_out+0x110/0x148 net/ipv4/ip_output.c:131
iptunnel_xmit+0x50c/0xd38 net/ipv4/ip_tunnel_core.c:97
udp_tunnel_xmit_skb+0x220/0x348 net/ipv4/udp_tunnel_core.c:187
tipc_udp_xmit+0x75c/0x9c0 net/tipc/udp_media.c:202
tipc_udp_send_msg+0x214/0x374 net/tipc/udp_media.c:274
tipc_bearer_xmit_skb+0x260/0x3b0 net/tipc/bearer.c:576
tipc_enable_bearer net/tipc/bearer.c:366 [inline]
__tipc_nl_bearer_enable+0xc90/0xfb0 net/tipc/bearer.c:1048
tipc_nl_bearer_enable+0x2c/0x48 net/tipc/bearer.c:1057
genl_family_rcv_msg_doit+0x1e4/0x2d4 net/netlink/genetlink.c:1114 |
| In the Linux kernel, the following vulnerability has been resolved:
ASoC: qcom: lpass-cpu: use DAI table index for playback constraints
The DAI ID is a hardware port ID and is not necessarily the index of
the corresponding entry in variant->dai_driver.
When configuring a DAI with LPAIF_I2SCTL_MODE_QUAD01, the probe code
currently uses dai_id to index variant->dai_driver. This is incorrect
for platforms where DAI IDs are sparse. For example, the IPQ806x MI2S
DAI has ID 4 while it is the only entry in the DAI driver table. If
that DAI is configured for QUAD01 and probe reaches this branch, the
code writes beyond that single entry via dai_driver[4] instead of
updating the DAI being processed.
Use the loop index i when updating the current DAI's playback channel
constraints, while retaining dai_id for indexing the hardware-port
specific playback SD-line mode array.
This fixes the incorrect DAI table access for platforms where the DAI
ID does not match its position in the driver table. |
| In the Linux kernel, the following vulnerability has been resolved:
namespace: handle mount locking for automounts correctly
If mounts are propagated across user namespaces, attach_recursive_mnt()
locks every copy of the source mount to protect overmounts from
vanishing and revealing the underlying files or directories.
The user namespace is taken from the caller's mount namespaces since
this is where the mounts end up. Except, that's not always true.
Automounts may legitimately get popped in by tasks located in a
different mount and user namespace during path lookup.
Then check doesn't make sense at that point. The copy in the namespace
of the parent - which may be the host's - is now locked and the host
cannot change the flags of its own mounts anymore.
Here's the reproducer:
- host has debugfs mounted nosuid,nodev,noexec and shared
- tracefs automount below it is not yet active
- hand a child process a directory descriptor on that mount
- child process enters auser and mount namespace
- child process' namespace now holds a locked copy of the host's debugfs
mount that receives propagation from it
- child process stats "tracing/." through the descriptor
- lookup runs on the host's mount so the automount lands below the host's mount
- propagation puts a copy below the child's copy
- both try to clear the flags on the mount they got, with a bind remount:
host, on its own automount: MS_REMOUNT|MS_BIND = EPERM
child, on the copy in its namespace: MS_REMOUNT|MS_BIND = 0
So the lock landed on the host's mount instead of the child's copy.
Congrats. So we need to compare with the owner of the namespace the
mount actually gets mounted on. For all regular cases that is the
caller's mount namespace and so nothing changes.
Detached trees in anonymous mount namespaces by be handed over via
SCM_RIGHTS or inherited in other ways on purpose so the attaching task's
mount namespace is authoritative, not the creator of the detached tree. |
| In the Linux kernel, the following vulnerability has been resolved:
namespace: refuse an automount below a mount that is in no namespace
It's possible to add autmounts even when the parent mount isn't in the
mount namespace of the caller. The only requirement we have is that the
parent mount namespace must not be NULL, i.e., unmounted.
Problem is that clone_private_mount() has MNT_NS_INTERNAL which makes
that trivially true. So that passes the test and attach_recursive_mnt()
accepts that as a mount point and funny enough, count_mounts()
dereferences MNT_NS_INTERNAL. The problem is it is an error pointer...
So we can reach this in userspace via fanotify. A filesystem mark on the
lower filesystem of an overlay reports paths on the layer clone and
reading the event hands out a descriptor on it. For example with debugfs
as the lower layer it goes kaboom:
openat(evfd, "tracing", O_DIRECTORY)
Oops: general protection fault
KASAN: null-ptr-deref in range [0x1d0-0x1d7]
RIP: 0010:count_mounts+0x35/0x200
attach_recursive_mnt
finish_automount
And since that sleeping beauty happens under namespace_sem held for
writing every mount operation on the system blocks from then on.
Congrats.
Use is_mounted() instead which rejects unmounted and internal mounts
alike. The open fails with EINVAL just as it did before
clone_private_mount() used MNT_NS_INTERNAL. |
| In the Linux kernel, the following vulnerability has been resolved:
unshare: don't drop active namespace references that were never taken
Active references on the namespaces of an nsproxy are taken when the
nsproxy is installed into a task in switch_task_namespaces() and
copy_namespaces() and dropped again by put_nsproxy() through
deactivate_nsproxy().
But ksys_unshare() calls put_nsproxy() on an nsproxy that was never
installed when set_cred_ucounts() fails. The new namespaces of that
nsproxy go from zero to minus one and the namespaces shared with the
caller lose a reference that belongs to the nsproxy the caller keeps
using:
WARNING: kernel/nscommon.c:171 at __ns_ref_active_put+0x1cd/0x230
nsproxy_ns_active_put
deactivate_nsproxy
ksys_unshare
Afterwards the namespaces the caller lives in aren't listed by listns()
anymore. set_cred_ucounts() only fails when alloc_ucounts() can't
allocate and it only allocates when the real uid of the caller differs
from its effective uid.
Commit cefd55bd2159 ("nsproxy: fix free_nsproxy() and simplify
create_new_namespaces()") separated the two cases on purpose.
nsproxy_free() frees an nsproxy that was prepared but never installed
and that's what a failed setns() uses in put_nsset(). Export it and use
it for a failed unshare() as well. |
| In the Linux kernel, the following vulnerability has been resolved:
ibmveth: h_free logical LAN on open-fail after register
ibmveth_open() registers the logical LAN, then allocates the RX
buffer pools. A pool failure jumps to out_free_buffer_pools without
h_free_logical_lan(), so PHYP still owns the buffer-list page when
it is unmapped. request_irq() failure already issued the hypercall
before taking the same label.
Move that h_free to the shared post-register unwind so both paths
deregister before the buffer list is unmapped. |
| In the Linux kernel, the following vulnerability has been resolved:
gve: fix XSK buffer leak when rings are stopped
GVE does not free XSK buffers when resetting ring state as a part of
stopping queues. This causes all XSK buffers which are posted to the
NIC to be leaked.
Free XSK buffers attached to an allocated buf_state when stopping rings.
This issue was hit in production. |
| In the Linux kernel, the following vulnerability has been resolved:
gve: fix napi_disable deadlock when attempting to disable XSK pools
When disabling XSK pools, GVE calls the unlocked versions of
napi_disable and napi_enable. However, the netdev lock has already been
acquired before ndo_bpf is called because GVE supports queue management
ops. Calling the unlocked versions of napi_disable/enable results in a
deadlock when attempting to disable XSK pools, as the thread attempts to
re-acquire a lock it already holds.
Update the NAPI calls to use the locked versions.
This issue was found in production. |
| In the Linux kernel, the following vulnerability has been resolved:
tcp: reject net_iov in zerocopy receive mapping hints
After copying a readable prefix, receive_fallback_to_copy() asks
tcp_zerocopy_set_hint_for_skb() where page mapping can resume. If the
next skb is unreadable, find_next_mappable_frag() passes its net_iov
fragment to can_map_frag().
skb_frag_page() returns NULL for a net_iov, but can_map_frag()
dereferences it in PageCompound(). A v7.2 KASAN run on a connected TCP
socket with 64 readable bytes followed by a 4096-byte NET_IOV_DMABUF
fragment reported:
BUG: KASAN: null-ptr-deref in can_map_frag
tcp_zerocopy_receive -> can_map_frag
Kernel panic - not syncing: KASAN: panic_on_warn set
The diagnostic inserted the net_iov directly because the test host has
no devmem-capable NIC. Hardware end-to-end reachability remains untested
and requires CONFIG_NET_DEVMEM plus a supported DMA-buf-bound RX queue.
Reject all net_iov fragments before skb_frag_page(). This covers both
DMABUF and IOURING net_iov types while leaving page-backed checks
unchanged. With the guard, the same queue copied the readable prefix,
returned a 4096-byte skip hint, and completed without a fault. |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: brcmfmac: fix P2P device removal race in brcmf_detach()
When the driver is removed while the user space process that created
the P2P device (e.g. wpa_supplicant) is still exiting, the P2P device
interface is removed twice and the kernel crashes.
The two paths are:
- wpa_supplicant, on exit, sends NL80211_CMD_DEL_INTERFACE for the P2P
device. nl80211_del_interface() holds RTNL and the wiphy mutex and
calls brcmf_p2p_del_vif(), which disables discovery and waits up to
1.5 s for BRCMF_E_IF_DEL. Then it calls brcmf_remove_interface(),
which unregisters the wdev and frees the vif and the ifp.
- brcmf_detach() sets the bus down, so BRCMF_E_IF_DEL never arrives,
and calls brcmf_remove_interface(ifp, false) for the same ifp.
brcmf_p2p_ifp_removed() reads ifp->vif and then blocks on
rtnl_lock(). When brcmf_p2p_del_vif() releases RTNL, it calls
cfg80211_unregister_wdev() on the wdev that was already unregistered
and freed.
The second list_del_rcu() of wdev->list faults on LIST_POISON2:
brcmfmac: brcmf_p2p_del_vif delete P2P vif
brcmfmac: brcmf_p2p_deinit_discovery enter
brcmfmac: brcmf_p2p_del_vif P2P: GO_NEG_PHASE status cleared
brcmfmac: brcmf_detach Enter
brcmfmac: brcmf_bus_change_state 1 -> 0
brcmfmac: brcmf_remove_interface Enter, bsscfgidx=1, ifidx=0
brcmfmac: brcmf_del_if Enter, bsscfgidx=1, ifidx=0
brcmfmac: brcmf_p2p_ifp_removed P2P: device interface removed
[1.5 s later, brcmf_p2p_del_vif() timed out]
brcmfmac: brcmf_remove_interface Enter, bsscfgidx=1, ifidx=0
brcmfmac: brcmf_del_if Enter, bsscfgidx=1, ifidx=0
brcmfmac: brcmf_p2p_ifp_removed P2P: device interface removed
Unable to handle kernel paging request at virtual address dead000000000122
Internal error: Oops: 96000044 [#1] PREEMPT_RT SMP
pc : _cfg80211_unregister_wdev+0x6c/0x264 [cfg80211]
Call trace:
_cfg80211_unregister_wdev+0x6c/0x264 [cfg80211]
cfg80211_unregister_wdev+0x10/0x1c [cfg80211]
brcmf_p2p_ifp_removed+0x84/0xb0 [brcmfmac]
brcmf_remove_interface+0x1f4/0x254 [brcmfmac]
brcmf_detach+0x88/0x180 [brcmfmac]
brcmf_sdio_remove+0x90/0x7b0 [brcmfmac]
brcmf_sdiod_remove+0x20/0xa0 [brcmfmac]
brcmf_ops_sdio_remove+0xbc/0x12c [brcmfmac]
sdio_bus_remove+0x38/0x144
device_release_driver_internal+0x1e8/0x2c0
device_release_driver+0x14/0x20
brcmf_sdio_bus_remove+0x2c/0x40 [brcmfmac]
brcmf_fwvid_unregister_vendor+0xd8/0x170 [brcmfmac]
__exit_compat+0x18/0x418 [brcmfmac_cyw]
__arm64_sys_delete_module+0x1ac/0x244
The log was taken with debug=0x406 on an i.MX 8M Plus board with a
CYW55513 (Sona IF513) on SDIO. The driver is the Ezurio backport of
brcmfmac from v6.18.22 on a 5.4-rt kernel. The code involved is the same
in mainline.
To reproduce:
1. Start wpa_supplicant on wlan0 and let it associate. It creates the
P2P device (iw dev shows "type P2P-device").
2. Stop wpa_supplicant and remove the driver without waiting for
wpa_supplicant to exit:
kill $(pidof wpa_supplicant)
rmmod brcmfmac_cyw brcmfmac
The crash is reproducible on that board.
For the interface without a netdev (the P2P device), take RTNL and the
wiphy mutex in brcmf_detach() before reading iflist, and remove it with
locked=true. If brcmf_p2p_del_vif() runs first, brcmf_detach() finds the
slot empty. If brcmf_detach() runs first, nl80211 does not find the wdev
any more. The interfaces with a netdev are removed as before, because
brcmf_del_if() takes RTNL on its own for the primary interface. |
| In the Linux kernel, the following vulnerability has been resolved:
vsock/virtio: account only unread bytes in read_skb()
After a partial stream receive, rx_bytes tracks the unread suffix while
buf_used and peer credit still cover the whole packet.
virtio_transport_read_skb() dequeues that packet but passes pkt_len for
both counters, underflowing rx_bytes.
On a connected CID_LOCAL stream with an SK_SKB verdict, a 40-byte read
from a 100-byte packet made SIOCINQ report -40, an empty recv return
ELOOP, and poll report the empty socket readable. After verdict detach,
receiving 40 bytes wrapped the counter to zero and hid those queued bytes
until one more byte arrived. The fixed run kept the counter balanced
and exposed all queued data immediately.
This was found during an LLM-assisted manual source audit of VSOCK
receive accounting while re-evaluating virtio_transport_read_skb() after
CVE-2024-50169.
Subtract only skb->len minus the VSOCK offset from rx_bytes. Retain the
full packet length for buf_used and peer credit. |
| In the Linux kernel, the following vulnerability has been resolved:
drm/imagination: Fix reference and vm_bo handling in remap()
When a map overlaps part of an existing mapping, pvr_vm_gpuva_remap()
splits the mapping into prev/next parts covering what the request did
not take, instead of creating something new. It gets two things wrong.
- A GEM reference is taken for each part but it's never needed and never
dropped, so it leaks one reference per split (remap-next-in-2m in
tests/imagination/pvr_vm_map.c):
CRITICAL: 33558528 bytes of shmem still held after close
- The parts still belong to the original object being split, but
pvr_vm_gpuva_remap() links them to ctx->gpuvm_bo, the new object's
vm_bo:
prev_va --obj--> BO_A BO_B <--obj-- vm_bo (ctx->gpuvm_bo)
\___________link___________/ (mismatch: BO_A != BO_B)
drm_gpuva_link() catches the mismatch:
WARNING: drivers/gpu/drm/drm_gpuvm.c:2108 at drm_gpuva_link+0x2ec/0x310
drm_WARN_ON(obj != vm_bo->obj)
Call trace:
drm_gpuva_link
pvr_vm_gpuva_remap
__drm_gpuvm_sm_map
pvr_vm_map
pvr_ioctl_vm_map
Link them to op->remap.unmap->va->vm_bo instead.
The locking of the GPUVA lists of the other objects touched by a split is
not addressed here; it is handled by switching the GPUVM to immediate
mode. |
| In the Linux kernel, the following vulnerability has been resolved:
flow_dissector: avoid u16 truncation of hlen in bpf_flow_dissect()
bpf_flow_dissect() sanitizes the offsets returned by the BPF program
with clamp_t(u16, ..., hlen).
If hlen is bigger than 65535, the upper bound is truncated before
the comparison. For instance, with hlen == 65536, both nhoff and
thoff are forced to zero, even if the program returned sane values.
This is the same class of bug as the one fixed in commit 99bda1ecbd56
("flow_dissector: avoid u16 truncation of skb->len when computing
thoff"). That fix does not cover the BPF path, because
__skb_flow_dissect() returns early when a BPF flow dissector
handles the packet.
struct bpf_flow_keys stores nhoff and thoff as u16, so cap hlen
to U16_MAX before clamping.
Found by sashiko while reviewing the commit above. |
| In the Linux kernel, the following vulnerability has been resolved:
btrfs: free iov when btrfs_uring_read_extent() fails
After btrfs_uring_read_extent(), the caller always jumped to out_acct.
That skips kfree(data->iov), which is only correct for -EIOCBQUEUED
where the deferred path owns the iov. On failure, fall through to
out_free instead. |
| In the Linux kernel, the following vulnerability has been resolved:
statmount: read the parent of an unmounted mount under mount_lock
statmount_mnt_basic() reads the ids of the parent through m->mnt_parent
with namespace_sem held for reading. That's fine for a mount that is
in a namespace. Everything above it is pinned by that namespace.
STATMOUNT_BY_FD also accepts a file descriptor on a mount that has
been unmounted on purpose and that only the file descriptor keeps alive.
If that mount stayed attached to its parent when it was unmounted the
parent is unmounted as well and nothing pins it for the child.
The final mntput() unmounts the children under mount_lock alone and
frees the parent afterwards. Concurrently, statmount_mnt_basic() reads
m->mnt_parent twice while that can happen and can easily dereference a
mount that's already gone.
Read the parent of an unmounted mount under mount_lock. The parent
can't be put while it is held and both ids come from the same mount. A
mounted mount's parent is pinned by the namespace and a mount can't
leave its namespace while namespace_sem is held, so the common case
takes no global lock. |
