{"cve":"CVE-2024-26645","nvd":{"published":"2024-03-26T16:15:12.207","modified":"2026-10-15T01:17:21.543","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Ensure visibility when inserting an element into tracing_map\n\nRunning the following two commands in parallel on a multi-processor\nAArch64 machine can sporadically produce an unexpected warning about\nduplicate histogram entries:\n\n $ while true; do\n     echo hist:key=id.syscall:val=hitcount > \\\n       /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/trigger\n     cat /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/hist\n     sleep 0.001\n   done\n $ stress-ng --sysbadaddr $(nproc)\n\nThe warning looks as follows:\n\n[ 2911.172474] ------------[ cut here ]------------\n[ 2911.173111] Duplicates detected: 1\n[ 2911.173574] WARNING: CPU: 2 PID: 12247 at kernel/trace/tracing_map.c:983 tracing_map_sort_entries+0x3e0/0x408\n[ 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)\n[ 2911.174738] Unloaded tainted modules: cppc_cpufreq(E):1\n[ 2911.180985] CPU: 2 PID: 12247 Comm: cat Kdump: loaded Tainted: G            E      6.7.0-default #2 1b58bbb22c97e4399dc09f92d309344f69c44a01\n[ 2911.182398] Hardware name: Amazon EC2 c7g.8xlarge/, BIOS 1.0 11/1/2018\n[ 2911.183208] pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)\n[ 2911.184038] pc : tracing_map_sort_entries+0x3e0/0x408\n[ 2911.184667] lr : tracing_map_sort_entries+0x3e0/0x408\n[ 2911.185310] sp : ffff8000a1513900\n[ 2911.185750] x29: ffff8000a1513900 x28: ffff0003f272fe80 x27: 0000000000000001\n[ 2911.186600] x26: ffff0003f272fe80 x25: 0000000000000030 x24: 0000000000000008\n[ 2911.187458] x23: ffff0003c5788000 x22: ffff0003c16710c8 x21: ffff80008017f180\n[ 2911.188310] x20: ffff80008017f000 x19: ffff80008017f180 x18: ffffffffffffffff\n[ 2911.189160] x17: 0000000000000000 x16: 0000000000000000 x15: ffff8000a15134b8\n[ 2911.190015] x14: 0000000000000000 x13: 205d373432323154 x12: 5b5d313131333731\n[ 2911.190844] x11: 00000000fffeffff x10: 00000000fffeffff x9 : ffffd1b78274a13c\n[ 2911.191716] x8 : 000000000017ffe8 x7 : c0000000fffeffff x6 : 000000000057ffa8\n[ 2911.192554] x5 : ffff0012f6c24ec0 x4 : 0000000000000000 x3 : ffff2e5b72b5d000\n[ 2911.193404] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0003ff254480\n[ 2911.194259] Call trace:\n[ 2911.194626]  tracing_map_sort_entries+0x3e0/0x408\n[ 2911.195220]  hist_show+0x124/0x800\n[ 2911.195692]  seq_read_iter+0x1d4/0x4e8\n[ 2911.196193]  seq_read+0xe8/0x138\n[ 2911.196638]  vfs_read+0xc8/0x300\n[ 2911.197078]  ksys_read+0x70/0x108\n[ 2911.197534]  __arm64_sys_read+0x24/0x38\n[ 2911.198046]  invoke_syscall+0x78/0x108\n[ 2911.198553]  el0_svc_common.constprop.0+0xd0/0xf8\n[ 2911.199157]  do_el0_svc+0x28/0x40\n[ 2911.199613]  el0_svc+0x40/0x178\n[ 2911.200048]  el0t_64_sync_handler+0x13c/0x158\n[ 2911.200621]  el0t_64_sync+0x1a8/0x1b0\n[ 2911.201115] ---[ end trace 0000000000000000 ]---\n\nThe problem appears to be caused by CPU reordering of writes issued from\n__tracing_map_insert().\n\nThe check for the presence of an element with a given key in this\nfunction is:\n\n val = READ_ONCE(entry->val);\n if (val && keys_match(key, val->key, map->key_size)) ...\n\nThe write of a new entry is:\n\n elt = get_free_elt(map);\n memcpy(elt->key, key, map->key_size);\n entry->val = elt;\n\nThe \"memcpy(elt->key, key, map->key_size);\" and \"entry->val = elt;\"\nstores may become visible in the reversed order on another CPU. This\nsecond CPU might then incorrectly determine that a new key doesn't match\nan already present val->key and subse\n---truncated---","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":[],"references":["https://git.kernel.org/stable/c/2b44760609e9eaafc9d234a6883d042fc21132a7","https://git.kernel.org/stable/c/5022b331c041e8c54b9a6a3251579bd1e8c0fc0b","https://git.kernel.org/stable/c/a1eebe76e187dbe11ca299f8dbb6e45d5b1889e7","https://git.kernel.org/stable/c/aef1cb00856ccfd614467cfb50b791278992e177","https://git.kernel.org/stable/c/bf4aeff7da85c3becd39fb73bac94122331c30fb"],"products":["debian:debian_linux","linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:47:51.568503435+00:00"},"epss":{"cve":"CVE-2024-26645","score":0.00242,"percentile":0.15223,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}