Medium 5.5Published Mar 26, 2024

CVE-2024-26645tracing: Ensure visibility when inserting an element into tracing_map

Updated under an hour ago (2026-10-19 07:00 UTC)

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In the Linux kernel, the following vulnerability has been resolved: tracing: Ensure visibility when inserting an element into tracing_map Running the following two commands in parallel on a multi-processor AArch64 machine can sporadically produce an unexpected warning about duplicate histogram entries: $ while true; do echo hist:key=id.syscall:val=hitcount > \ /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/trigger cat /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/hist sleep 0.001 done $ stress-ng --sysbadaddr $(nproc) The warning looks as follows: [ 2911.172474] ------------[ cut here ]------------ [ 2911.173111] Duplicates detected: 1 [ 2911.173574] WARNING: CPU: 2 PID: 12247 at kernel/trace/tracing_map.c:983 tracing_map_sort_entries+0x3e0/0x408 [ 2911.174702] Modules linked in: iscsi_ibft(E) iscsi_boot_sysfs(E) rfkill(E) af_packet(E) nls_iso8859_1(E) nls_cp437(E) vfat(E) fat(E) ena(E) tiny_power_button(E) qemu_fw_cfg(E) button(E) fuse(E) efi_pstore(E) ip_tables(E) x_tables(E) xfs(E) libcrc32c(E) aes_ce_blk(E) aes_ce_cipher(E) crct10dif_ce(E) polyval_ce(E) polyval_generic(E) ghash_ce(E) gf128mul(E) sm4_ce_gcm(E) sm4_ce_ccm(E) sm4_ce(E) sm4_ce_cipher(E) sm4(E) sm3_ce(E) sm3(E) sha3_ce(E) sha512_ce(E) sha512_arm64(E) sha2_ce(E) sha256_arm64(E) nvme(E) sha1_ce(E) nvme_core(E) nvme_auth(E) t10_pi(E) sg(E) scsi_mod(E) scsi_common(E) efivarfs(E) [ 2911.174738] Unloaded tainted modules: cppc_cpufreq(E):1 [ 2911.180985] CPU: 2 PID: 12247 Comm: cat Kdump: loaded Tainted: G E 6.7.0-default #2 1b58bbb22c97e4399dc09f92d309344f69c44a01 [ 2911.182398] Hardware name: Amazon EC2 c7g.8xlarge/, BIOS 1.0 11/1/2018 [ 2911.183208] pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) [ 2911.184038] pc : tracing_map_sort_entries+0x3e0/0x408 [ 2911.184667] lr : tracing_map_sort_entries+0x3e0/0x408 [ 2911.185310] sp : ffff8000a1513900 [ 2911.185750] x29: ffff8000a1513900 x28: ffff0003f272fe80 x27: 0000000000000001 [ 2911.186600] x26: ffff0003f272fe80 x25: 0000000000000030 x24: 0000000000000008 [ 2911.187458] x23: ffff0003c5788000 x22: ffff0003c16710c8 x21: ffff80008017f180 [ 2911.188310] x20: ffff80008017f000 x19: ffff80008017f180 x18: ffffffffffffffff [ 2911.189160] x17: 0000000000000000 x16: 0000000000000000 x15: ffff8000a15134b8 [ 2911.190015] x14: 0000000000000000 x13: 205d373432323154 x12: 5b5d313131333731 [ 2911.190844] x11: 00000000fffeffff x10: 00000000fffeffff x9 : ffffd1b78274a13c [ 2911.191716] x8 : 000000000017ffe8 x7 : c0000000fffeffff x6 : 000000000057ffa8 [ 2911.192554] x5 : ffff0012f6c24ec0 x4 : 0000000000000000 x3 : ffff2e5b72b5d000 [ 2911.193404] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0003ff254480 [ 2911.194259] Call trace: [ 2911.194626] tracing_map_sort_entries+0x3e0/0x408 [ 2911.195220] hist_show+0x124/0x800 [ 2911.195692] seq_read_iter+0x1d4/0x4e8 [ 2911.196193] seq_read+0xe8/0x138 [ 2911.196638] vfs_read+0xc8/0x300 [ 2911.197078] ksys_read+0x70/0x108 [ 2911.197534] __arm64_sys_read+0x24/0x38 [ 2911.198046] invoke_syscall+0x78/0x108 [ 2911.198553] el0_svc_common.constprop.0+0xd0/0xf8 [ 2911.199157] do_el0_svc+0x28/0x40 [ 2911.199613] el0_svc+0x40/0x178 [ 2911.200048] el0t_64_sync_handler+0x13c/0x158 [ 2911.200621] el0t_64_sync+0x1a8/0x1b0 [ 2911.201115] ---[ end trace 0000000000000000 ]--- The problem appears to be caused by CPU reordering of writes issued from __tracing_map_insert(). The check for the presence of an element with a given key in this function is: val = READ_ONCE(entry->val); if (val && keys_match(key, val->key, map->key_size)) ... The write of a new entry is: elt = get_free_elt(map); memcpy(elt->key, key, map->key_size); entry->val = elt; The "memcpy(elt->key, key, map->key_size);" and "entry->val = elt;" stores may become visible in the reversed order on another CPU. This second CPU might then incorrectly determine that a new key doesn't match an already present val->key and subse ---truncated---

CVSS: 5.5 MEDIUM (v3.1, NVD)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: Oct 15, 2026
First seen by InfoSec Signals: Oct 15, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from c193707dde77ace92a649cd59a17e105e2fbeaef before 5022b331c041e8c54b9a6a3251579bd1e8c0fc0b; from c193707dde77ace92a649cd59a17e105e2fbeaef before dad9b28f675ed99b4dec261db2a397efeb80b74c; from c193707dde77ace92a649cd59a17e105e2fbeaef before ef70dfa0b1e5084f32635156c9a5c795352ad860; from c193707dde77ace92a649cd59a17e105e2fbeaef before aef1cb00856ccfd614467cfb50b791278992e177; from c193707dde77ace92a649cd59a17e105e2fbeaef before f4f7e696db0274ff560482cc52eddbf0551d4b7a; from c193707dde77ace92a649cd59a17e105e2fbeaef before a1eebe76e187dbe11ca299f8dbb6e45d5b1889e7; from c193707dde77ace92a649cd59a17e105e2fbeaef before bf4aeff7da85c3becd39fb73bac94122331c30fb; from c193707dde77ace92a649cd59a17e105e2fbeaef before 2b44760609e9eaafc9d234a6883d042fc21132a7	CNA record
Siemens RUGGEDCOM RST2428P siemens:ruggedcom_rst2428p (from the name)	all versions not affected	CISA ADP
Siemens SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family siemens:scalance_xc_300_xr_300_xc_400_xr_500wg_xr_500_family (from the name)	all versions not affected	CISA ADP
Siemens SCALANCE XCM-/XRM-/XCH-/XRH-300 family siemens:scalance_xcm_xrm_xch_xrh_300_family (from the name)	all versions not affected	CISA ADP
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)	from V3.1.0 before V3.1.5	CISA ADP
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name)	from V3.1.0 before V3.1.5	CISA ADP
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)	from V3.1.0 before V3.1.5	CISA ADP
linux linux_kernel linux:linux_kernel	from 4.17 before 4.19.307; from 4.20 before 5.4.269; from 5.5 before 5.10.210; from 5.11 before 5.15.149; from 5.16 before 6.1.76; from 6.2 before 6.7.3; 6.8	NVD
debian debian_linux debian:debian_linux	10.0	NVD

References

https://git.kernel.org/stable/c/5022b331c041e8c54b9a6a3251579bd1e8c0fc0bpatch
https://git.kernel.org/stable/c/dad9b28f675ed99b4dec261db2a397efeb80b74cpatch
https://git.kernel.org/stable/c/ef70dfa0b1e5084f32635156c9a5c795352ad860patch
https://git.kernel.org/stable/c/aef1cb00856ccfd614467cfb50b791278992e177patch
https://git.kernel.org/stable/c/f4f7e696db0274ff560482cc52eddbf0551d4b7apatch
https://git.kernel.org/stable/c/a1eebe76e187dbe11ca299f8dbb6e45d5b1889e7patch
https://git.kernel.org/stable/c/bf4aeff7da85c3becd39fb73bac94122331c30fbpatch
https://git.kernel.org/stable/c/2b44760609e9eaafc9d234a6883d042fc21132a7patch
https://lists.debian.org/debian-lts-announce/2024/06/msg00017.htmlmailing-list
https://lists.debian.org/debian-lts-announce/2024/06/msg00020.htmlmailing-list
https://cert-portal.siemens.com/productcert/html/ssa-398330.html
https://cert-portal.siemens.com/productcert/html/ssa-613116.html

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.