Red Hat Linux Linux Kernel Vulnerabilities & Security Advisories
2150 advisories tracked · Red Hat Security Data API · 1 listed in the CISA Known Exploited Vulnerabilities catalog
Every row below is a published Red Hat Linux advisory that VulniPulse classified as Linux Kernel, with the CVEs, affected and fixed releases and exploitation status the vendor stated. Severity mix: 782 high, 1365 medium, 1 low.
Android app · Google Play
Monitor Red Hat CVEs from your phone.
Choose a whole vendor or a precise platform, then receive matching security advisories by phone notification, email, or both. Coverage follows 32 official vendor sources and 160+ reviewed platform categories.
Source
Red Hat Security Data API
Red Hat Enterprise Linux errata (RHSA) via the official Red Hat Security Data API — CVE severity, CVSS and affected packages. A credential-free official source.
Latest Red Hat Linux Kernel advisories
Medium [CVE-2026-53083] Fix RCU stall in bpf_fd_array_map_clear
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix RCU stall in bpf_fd_array_map_clear() Add a missing cond_resched() in bpf_fd_array_map_clear() loop. For PROG_ARRAY maps with many entries this loop calls prog_array_map_poke_run() per entry which can be expensive, and without yielding this can cause RCU stalls under load: rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 30932 Comm: kworker/0:2 Not tainted 6.14.0-13195-g967e8def1100 #2 PREEMPT(undef) Workqueue: events prog_array_map_clear_deferred RIP: 0010:write_comp_data+0x38/0x90 kernel/kcov.c:246 Call Trace: prog_array_map_poke_run+0x77/0x380 kernel/bpf/arraymap.c:1096 __fd_array_map_delete_elem+0x197/0x310 kernel/bpf/arraymap.c:925 bpf_fd_array_map_clear kernel/bpf/arraymap.c:1000 [inline] prog_array_map_clear_deferred+0x119/0x1b0 kernel/bpf/arraymap.c:1141 process_one_work+0x898/0x19d0 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x770/0x10b0 kernel/workqueue.c:3400 kthread+0x465/0x880 kernel/kthread.c:464 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x19/0x30 arch/x86/entry/entry_64.S:245 A missing `cond_resched()` in the `bpf_fd_array_map_clear()` loop, specifically when handling BPF (Berkeley Packet Filter) `PROG_ARRAY` maps with numerous entries, can lead to an RCU (Read-Copy Update) stall.
Medium [CVE-2026-53123] wake raid456 reshape waiters before suspend
In the Linux kernel, the following vulnerability has been resolved: md: wake raid456 reshape waiters before suspend During raid456 reshape, direct IO across the reshape position can sleep in raid5_make_request() waiting for reshape progress while still holding an active_io reference. If userspace then freezes reshape and writes md/suspend_lo or md/suspend_hi, mddev_suspend() kills active_io and waits for all in-flight IO to drain. This can deadlock: the IO needs reshape progress to continue, but the reshape thread is already frozen, so the active_io reference is never dropped and suspend never completes. raid5_prepare_suspend() already wakes wait_for_reshape for dm-raid. Do the same for normal md suspend when reshape is already interrupted, so waiting raid456 IO can abort, drop its reference, and let suspend finish. The mdadm test tests/25raid456-reshape-deadlock reproduces the hang. A flaw was found in the Linux kernel's Multiple Device (MD) driver, specifically within the raid456 reshape functionality. A local user could trigger a deadlock by freezing the reshape process and writing to the md/suspend_lo or md/suspend_hi files while direct I/O operations are in progress. This condition prevents the system from completing the suspend operation, leading to a Denial of Service (DoS). Red Hat severity: Low — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H).
Medium [CVE-2026-52984] fix queue limit check to include reordered packets
In the Linux kernel, the following vulnerability has been resolved: net/sched: netem: fix queue limit check to include reordered packets The queue limit check in netem_enqueue() uses q->t_len which only counts packets in the internal tfifo. Packets placed in sch->q by the reorder path (__qdisc_enqueue_head) are not counted, allowing the total queue occupancy to exceed sch->limit under reordering. A flaw was found in the Linux kernel's networking scheduler (netem). The queue limit check in the `netem_enqueue()` function does not properly account for reordered packets, allowing the total queue occupancy to exceed its configured limit. This oversight can lead to a Denial of Service (DoS) condition, where network traffic processing is disrupted due to an overloaded queue. Red Hat severity: Low — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-770. Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 9. Will not fix / out of support: Red Hat Enterprise Linux 6. Red Hat does not currently list a fixing RHSA for this CVE. Affected products named by the advisory: Red Hat package: kernel-rt.
Medium [CVE-2026-53090] Fix ld_{abs,ind} failure path analysis in subprogs
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix ld_{abs,ind} failure path analysis in subprogs Usage of ld_{abs,ind} instructions got extended into subprogs some time ago via commit 09b28d76eac4 ("bpf: Add abnormal return checks."). These are only allowed in subprograms when the latter are BTF annotated and have scalar return types. The code generator in bpf_gen_ld_abs() has an abnormal exit path (r0=0 + exit) from legacy cBPF times. While the enforcement is on scalar return types, the verifier must also simulate the path of abnormal exit if the packet data load via ld_{abs,ind} failed. This is currently not the case. Fix it by having the verifier simulate both success and failure paths, and extend it in similar ways as we do for tail calls. The success path (r0=unknown, continue to next insn) is pushed onto stack for later validation and the r0=0 and return to the caller is done on the fall-through side. A flaw was found in the Linux kernel's Berkeley Packet Filter (BPF) verifier. When `ld_{abs,ind}` instructions are used in BPF subprograms, the verifier fails to correctly simulate the abnormal exit path if packet data loading fails. This oversight could lead to unexpected behavior or bypass of security checks within the BPF execution environment.
Medium [CVE-2026-53105] prevent NULL vif dereference in mt7925_mac_write_txwi
In the Linux kernel, the following vulnerability has been resolved: wifi: mt76: mt7925: prevent NULL vif dereference in mt7925_mac_write_txwi Check for a NULL `vif` before accessing `ieee80211_vif_is_mld(vif)` to avoid a potential kernel panic in scenarios where `vif` might not be initialized. A flaw was found in the Linux kernel's Wi-Fi subsystem, specifically within the mt76: mt7925 driver. This vulnerability occurs due to a missing check for a NULL 'vif' (Virtual Interface) before it is accessed. An attacker could potentially trigger a kernel panic by exploiting scenarios where the 'vif' might not be initialized, leading to a system crash and a Denial of Service (DoS). Red Hat severity: Moderate — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-476. Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 9. Red Hat does not currently list a fixing RHSA for this CVE. Affected products named by the advisory: Red Hat package: kernel-rt.
Medium [CVE-2026-53080] fix NULL dereference of "old" filters before change
In the Linux kernel, the following vulnerability has been resolved: net/sched: cls_fw: fix NULL dereference of "old" filters before change() Like pointed out by Sashiko [1], since commit ed76f5edccc9 ("net: sched: protect filter_chain list with filter_chain_lock mutex") TC filters are added to a shared block and published to datapath before their ->change() function is called. This is a problem for cls_fw: an invalid filter created with the "old" method can still classify some packets before it is destroyed by the validation logic added by Xiang. Affected products named by the advisory: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9; and 1 more.
Medium [CVE-2026-53004] fix OOB write to userspace in sctp_getsockopt_peer_auth_chunks
In the Linux kernel, the following vulnerability has been resolved: sctp: fix OOB write to userspace in sctp_getsockopt_peer_auth_chunks sctp_getsockopt_peer_auth_chunks() checks that the caller's optval buffer is large enough for the peer AUTH chunk list with if (len gauth_chunks, which lives at offset offsetof(struct sctp_authchunks, gauth_chunks) == 8 inside optval. The check is missing the sizeof(struct sctp_authchunks) = 8-byte header. When the caller supplies len == num_chunks (for any num_chunks > 0) the test passes but copy_to_user() writes sizeof(struct sctp_authchunks) = 8 bytes past the declared buffer. Reproducer confirms on v7.0-13-generic: an unprivileged userspace caller that opens a loopback SCTP association with AUTH enabled, queries num_chunks with a short optval, then issues the real getsockopt with len == num_chunks and sentinel bytes painted past the buffer observes those sentinel bytes overwritten with the peer's AUTH chunk type. The bytes written are under the peer's control but land in the caller's own userspace; this is not a kernel memory corruption, but it is a kernel-side contract violation that can silently corrupt adjacent userspace data. A flaw was found in the Linux kernel's Stream Control Transmission Protocol (SCTP) implementation.
Medium [CVE-2026-53122] fix deadlock between reflink and transaction commit when using flushoncommit
In the Linux kernel, the following vulnerability has been resolved: btrfs: fix deadlock between reflink and transaction commit when using flushoncommit When using the flushoncommit mount option, we can have a deadlock between a transaction commit and a reflink operation that copied an inline extent to an offset beyond the current i_size of the destination node. This means we copied the inline extent's data to a folio of inode Y that is beyond its EOF, using a call to copy_inline_to_page(); 2) Task B starts a transaction commit and calls btrfs_start_delalloc_flush() to flush delalloc; 3) The delalloc flushing sees the new dirty folio of inode Y and when it attempts to flush it, it ends up at extent_writepage() and sees that the offset of the folio is beyond the i_size of inode Y, so it attempts to invalidate the folio by calling folio_invalidate(), which ends up at btrfs' folio invalidate callback - btrfs_invalidate_folio(). Affected products named by the advisory: Red Hat Enterprise Linux 10; Red Hat package: kernel.
Medium [CVE-2026-53044] Fix incorrect ARRAY_SIZE in fabric lookup tables
In the Linux kernel, the following vulnerability has been resolved: soc/tegra: cbb: Fix incorrect ARRAY_SIZE in fabric lookup tables Fix incorrect ARRAY_SIZE usage in fabric lookup tables which could cause out-of-bounds access during target timeout lookup. This issue could allow a local attacker to cause a denial of service (DoS) or potentially lead to information disclosure. Red Hat severity: Moderate — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-131. Affected Red Hat products: Red Hat Enterprise Linux 10. Red Hat does not currently list a fixing RHSA for this CVE. Affected products named by the advisory: Red Hat package: kernel.
Medium [CVE-2026-53081] Enforce regsafe base id consistency for BPF_ADD_CONST scalars
In the Linux kernel, the following vulnerability has been resolved: bpf: Enforce regsafe base id consistency for BPF_ADD_CONST scalars When regsafe() compares two scalar registers that both carry BPF_ADD_CONST, check_scalar_ids() maps their full compound id (aka base | BPF_ADD_CONST flag) as one idmap entry. However, it never verifies that the underlying base ids, that is, with the flag stripped are consistent with existing idmap mappings. This allows construction of two verifier states where the old state has R3 = R2 + 10 (both sharing base id A) while the current state has R3 = R4 + 10 (base id C, unrelated to R2). The idmap creates two independent entries: A->B (for R2) and A|flag->C|flag (for R3), without catching that A->C conflicts with A->B. State pruning then incorrectly succeeds. Fix this by additionally verifying base ID mapping consistency whenever BPF_ADD_CONST is set: after mapping the compound ids, also invoke check_ids() on the base IDs (flag bits stripped). This ensures that if A was already mapped to B from comparing the source register, any ADD_CONST derivative must also derive from B, not an unrelated C. A flaw was found in the Linux kernel's Berkeley Packet Filter (BPF) verifier. This vulnerability occurs due to inconsistent base ID mapping when the `regsafe()` function compares scalar registers with `BPF_ADD_CONST` values.
Medium [CVE-2026-53084] return VMA snapshot from task_vma iterator
In the Linux kernel, the following vulnerability has been resolved: bpf: return VMA snapshot from task_vma iterator Holding the per-VMA lock across the BPF program body creates a lock ordering problem when helpers acquire locks that depend on mmap_lock: vm_lock -> i_rwsem -> mmap_lock -> vm_lock Snapshot the VMA under the per-VMA lock in _next() via memcpy(), then drop the lock before returning. The verifier only trusts vm_mm and vm_file pointers (see BTF_TYPE_SAFE_TRUSTED_OR_NULL in verifier.c). vm_file is reference- counted with get_file() under the lock and released via fput() on the next iteration or in _destroy(). vm_mm is already correct because lock_vma_under_rcu() verifies vma->vm_mm == mm. All other pointers are left as-is by memcpy() since the verifier treats them as untrusted. A flaw was found in the Linux kernel's Berkeley Packet Filter (BPF) subsystem. This issue could potentially lead to system instability or unexpected behavior due to incorrect handling of virtual memory area (VMA) locks. Red Hat severity: Moderate — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-833. Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 9. Red Hat does not currently list a fixing RHSA for this CVE. Affected products named by the advisory: Red Hat package: kernel-rt.
Medium [CVE-2026-53110] Zero-extend bpf prog return values and kfunc arguments
In the Linux kernel, the following vulnerability has been resolved: s390/bpf: Zero-extend bpf prog return values and kfunc arguments s390x ABI requires callers to zero-extend unsigned arguments and sign-extend signed arguments, and callees to zero-extend unsigned return values and sign-extend signed return values. s390 BPF JIT currently implements only sign extension. Fix this omission and implement zero extension too. A flaw was found in the Linux kernel's BPF (Berkeley Packet Filter) JIT (Just-In-Time) compiler for the s390x architecture. This could lead to unexpected behavior or data integrity issues when BPF programs interact with kernel functions on s390x systems. The default Red Hat Enterprise Linux kernel prevents unprivileged users from being able to use eBPF by the kernel.unprivileged_bpf_disabled sysctl. This would require a privileged user with CAP_SYS_ADMIN or root to be able to abuse this flaw reducing its attack space. Red Hat severity: Moderate — CVSS 6.4 (CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H). Weakness: CWE-681. Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 9. Red Hat does not currently list a fixing RHSA for this CVE. Affected products named by the advisory: Red Hat package: kernel-rt.
Medium [CVE-2026-53012] fix IPv6 route referencing IPv4 nexthop
In the Linux kernel, the following vulnerability has been resolved: nexthop: fix IPv6 route referencing IPv4 nexthop syzbot reported a panic [1] [2]. When an IPv6 nexthop is replaced with an IPv4 nexthop, the has_v4 flag of all groups containing this nexthop is not updated. This is because nh_group_v4_update is only called when replacing AF_INET to AF_INET6, but the reverse direction (AF_INET6 to AF_INET) is missed. This allows a stale has_v4=false to bypass fib6_check_nexthop, causing IPv6 routes to be attached to groups that effectively contain only AF_INET members. Subsequent route lookups then call nexthop_fib6_nh() which returns NULL for the AF_INET member, leading to a NULL pointer dereference. Fix by calling nh_group_v4_update whenever the family changes, not just AF_INET to AF_INET6. Reproducer: # AF_INET6 blackhole ip -6 nexthop add id 1 blackhole # group with has_v4=false ip nexthop add id 100 group 1 # replace with AF_INET (no -6), has_v4 stays false ip nexthop replace id 1 blackhole # pass stale has_v4 check ip -6 route add 2001:db8::/64 nhid 100 # panic ping -6 2001:db8::1 [1] [2] A flaw was found in the Linux kernel's networking subsystem. A local attacker could exploit this issue by crafting specific nexthop configurations, causing a NULL pointer dereference and ultimately leading to a system panic, resulting in a Denial of Service (DoS).
Medium [CVE-2026-52955] Fix potential out-of-bounds access in crush_decode
In the Linux kernel, the following vulnerability has been resolved: libceph: Fix potential out-of-bounds access in crush_decode() A message of type CEPH_MSG_OSD_MAP containing a crush map with at least one bucket has two fields holding the bucket algorithm. This is the case because the first algorithm field (alg) is used to allocate the correct amount of memory for a bucket of this type, while the second algorithm field inside the bucket (b->alg) is used in the subsequent processing. This patch fixes the issue by adding a check that compares alg and b->alg and aborts the processing in case they differ. Furthermore, b->alg is set to 0 in this case, because the destruction of the crush map also uses this field to determine the bucket type, which can again result in an out-of-bounds access when trying to free the memory pointed to by the fields of the bucket. To correctly free the memory allocated for the bucket in such a case, the corresponding call to kfree is moved from the algorithm-specific crush_destroy_bucket functions to the generic crush_destroy_bucket(). A remote attacker could send a specially crafted `CEPH_MSG_OSD_MAP` message where two internal fields, `alg` and `b->alg`, contain differing bucket algorithm values.
Medium [CVE-2026-53111] Fix the null pointer dereference issue in bpf_lwt_xmit_push_encap
In the Linux kernel, the following vulnerability has been resolved: bpf: test_run: Fix the null pointer dereference issue in bpf_lwt_xmit_push_encap The bpf_lwt_xmit_push_encap helper needs to access skb_dst(skb)->dev to calculate the needed headroom: err = skb_cow_head(skb, len + LL_RESERVED_SPACE(skb_dst(skb)->dev)); But skb->_skb_refdst may not be initialized when the skb is set up by bpf_prog_test_run_skb function. Affected products named by the advisory: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9; Red Hat package: kernel-rt.
Medium [CVE-2026-52963] Bound MIDI endpoint descriptor scans
In the Linux kernel, the following vulnerability has been resolved: ALSA: usb-audio: Bound MIDI endpoint descriptor scans snd_usbmidi_get_ms_info() validates the internal MIDIStreaming endpoint descriptor size before using baAssocJackID[], but the descriptor walker can still return a class-specific endpoint descriptor whose bLength exceeds the remaining bytes in the endpoint-extra scan. That leaves later flexible-array reads bounded by bLength, but not by the remaining bytes in the endpoint-extra scan. Stop walking when bLength is zero or extends past the remaining endpoint-extra scan. A flaw was found in the Linux kernel's Advanced Linux Sound Architecture (ALSA) USB audio driver. The driver's handling of MIDI (Musical Instrument Digital Interface) endpoint descriptors did not properly bound scans, allowing it to read beyond the intended memory buffer. This out-of-bounds read could potentially lead to information disclosure or cause system instability. Red Hat severity: Moderate — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-125. Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9. Will not fix / out of support: Red Hat Enterprise Linux 6. Red Hat does not currently list a fixing RHSA for this CVE.
Medium [CVE-2026-52975] implement proper RCU rules for port->aggregator
In the Linux kernel, the following vulnerability has been resolved: bonding: 3ad: implement proper RCU rules for port->aggregator syzbot found a data-race in bond_3ad_get_active_agg_info / bond_3ad_state_machine_handler [1] which hints at lack of proper RCU implementation. Affected products named by the advisory: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; and 2 more.
Medium [CVE-2026-53014] fix wrong device for mac_header_xmit check in tcf_blockcast_redir
In the Linux kernel, the following vulnerability has been resolved: net/sched: act_mirred: fix wrong device for mac_header_xmit check in tcf_blockcast_redir In tcf_blockcast_redir(), when iterating block ports to redirect packets to multiple devices, the mac_header_xmit flag is queried from the wrong device. The loop sends to dev_prev but queries dev_is_mac_header_xmit(dev) — which is the NEXT device in the iteration, not the one being sent to. This causes tcf_mirred_to_dev() to make incorrect decisions about whether to push or pull the MAC header. When the block contains mixed device types (e.g., an ethernet veth and a tunnel device), intermediate devices get the wrong mac_header_xmit flag, leading to skb header corruption. In the worst case, skb_push_rcsum with an incorrect mac_len can exhaust headroom and panic. The last device in the loop is handled correctly (line 365-366 uses dev_is_mac_header_xmit(dev_prev)), confirming this is a copy-paste oversight for the intermediate devices. Fix by using dev_prev instead of dev for the mac_header_xmit query, consistent with the device actually being sent to. When the kernel's traffic control (TC) subsystem processes network packets for redirection across different types of network devices, it can incorrectly handle packet headers. This can lead to corruption of network packet data.
Medium [CVE-2026-53037] fix deadlock in hid_post_reset
In the Linux kernel, the following vulnerability has been resolved: HID: usbhid: fix deadlock in hid_post_reset() You can build a USB device that includes a HID component and a storage or UAS component. The components can be reset only together. That means that hid_pre_reset() and hid_post_reset() are in the block IO error handling. Hence no memory allocation used in them may do block IO because the IO can deadlock on the mutex held while resetting a device and calling the interface drivers. Use GFP_NOIO for all allocations in them. This vulnerability occurs when a USB device, containing both HID and storage or Universal Attached SCSI (UAS) components, is reset. During the reset process, memory allocation operations within the `hid_post_reset()` function can attempt block input/output (I/O) while a mutex is held, leading to a deadlock. This can result in a Denial of Service (DoS) for the affected system. Red Hat severity: Low — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-833. Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9. Will not fix / out of support: Red Hat Enterprise Linux 6. Red Hat does not currently list a fixing RHSA for this CVE. Affected products named by the advisory: Red Hat package: kernel-rt.
Medium [CVE-2026-53064] dm cache: fix null-deref with concurrent writes in passthrough mode
In the Linux kernel, the following vulnerability has been resolved: dm cache: fix null-deref with concurrent writes in passthrough mode In passthrough mode, when dm-cache starts to invalidate a cache entry and bio prison cell lock fails due to concurrent write to the same cached block, mg->cell remains NULL. The error path in invalidate_complete() attempts to unlock and free the cell unconditionally, causing a NULL pointer dereference: KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 0 UID: 0 PID: 134 Comm: fio Not tainted 6.19.0-rc7 #3 PREEMPT RIP: 0010:dm_cell_unlock_v2+0x3f/0x210 Call Trace: invalidate_complete+0xef/0x430 map_bio+0x130f/0x1a10 cache_map+0x320/0x6b0 __map_bio+0x458/0x510 dm_submit_bio+0x40e/0x16d0 __submit_bio+0x419/0x870 Reproduce steps: 1. Create a cache device dmsetup create cmeta --table "0 8192 linear /dev/sdc 0" dmsetup create cdata --table "0 131072 linear /dev/sdc 8192" dmsetup create corig --table "0 262144 linear /dev/sdc 262144" dd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1 oflag=direct dmsetup create cache --table "0 262144 cache /dev/mapper/cmeta \ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0" 2. Promote the first data block into cache fio --filename=/dev/mapper/cache --name=populate --rw=write --bs=4k \ --direct=1 --size=64k 3.