{"id":"CVE-2023-52761","revision":"c2e87a772adb471f81dd01269038596b","records":[{"revision":"c2e87a772adb471f81dd01269038596b","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2023-52761","aliases":[],"title":"riscv: VMAP_STACK overflow detection thread-safe","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nriscv: VMAP_STACK overflow detection thread-safe\n\ncommit 31da94c25aea (\"riscv: add VMAP_STACK overflow detection\") added\nsupport for CONFIG_VMAP_STACK. If overflow is detected, CPU switches to\n`shadow_stack` temporarily before switching finally to per-cpu\n`overflow_stack`.\n\nIf two CPUs/harts are racing and end up in over flowing kernel stack, one\nor both will end up corrupting each other state because `shadow_stack` is\nnot per-cpu. This patch optimizes per-cpu overflow stack switch by\ndirectly picking per-cpu `overflow_stack` and gets rid of `shadow_stack`.\n\nFollowing are the changes in this patch\n\n - Defines an asm macro to obtain per-cpu symbols in destination\n register.\n - In entry.S, when overflow is detected, per-cpu overflow stack is\n located using per-cpu asm macro. Computing per-cpu symbol requires\n a temporary register. x31 is saved away into CSR_SCRATCH\n (CSR_SCRATCH is anyways zero since we're in kernel).\n\nPlease see Links for additional relevant disccussion and alternative\nsolution.\n\nTested by `echo EXHAUST_STACK > /sys/kernel/debug/provoke-crash/DIRECT`\nKernel crash log below\n\n Insufficient stack space to handle exception!/debug/provoke-crash/DIRECT\n Task stack: [0xff20000010a98000..0xff20000010a9c000]\n Overflow stack: [0xff600001f7d98370..0xff600001f7d99370]\n CPU: 1 PID: 205 Comm: bash Not tainted 6.1.0-rc2-00001-g328a1f96f7b9 #34\n Hardware name: riscv-virtio,qemu (DT)\n epc : __memset+0x60/0xfc\n ra : recursive_loop+0x48/0xc6 [lkdtm]\n epc : ffffffff808de0e4 ra : ffffffff0163a752 sp : ff20000010a97e80\n gp : ffffffff815c0330 tp : ff600000820ea280 t0 : ff20000010a97e88\n t1 : 000000000000002e t2 : 3233206874706564 s0 : ff20000010a982b0\n s1 : 0000000000000012 a0 : ff20000010a97e88 a1 : 0000000000000000\n a2 : 0000000000000400 a3 : ff20000010a98288 a4 : 0000000000000000\n a5 : 0000000000000000 a6 : fffffffffffe43f0 a7 : 00007fffffffffff\n s2 : ff20000010a97e88 s3 : ffffffff01644680 s4 : ff20000010a9be90\n s5 : ff600000842ba6c0 s6 : 00aaaaaac29e42b0 s7 : 00fffffff0aa3684\n s8 : 00aaaaaac2978040 s9 : 0000000000000065 s10: 00ffffff8a7cad10\n s11: 00ffffff8a76a4e0 t3 : ffffffff815dbaf4 t4 : ffffffff815dbaf4\n t5 : ffffffff815dbab8 t6 : ff20000010a9bb48\n status: 0000000200000120 badaddr: ff20000010a97e88 cause: 000000000000000f\n Kernel panic - not syncing: Kernel stack overflow\n CPU: 1 PID: 205 Comm: bash Not tainted 6.1.0-rc2-00001-g328a1f96f7b9 #34\n Hardware name: riscv-virtio,qemu (DT)\n Call Trace:\n [] dump_backtrace+0x30/0x38\n [] show_stack+0x40/0x4c\n [] dump_stack_lvl+0x44/0x5c\n [] dump_stack+0x18/0x20\n [] panic+0x126/0x2fe\n [] walk_stackframe+0x0/0xf0\n [] recursive_loop+0x48/0xc6 [lkdtm]\n SMP: stopping secondary CPUs\n ---[ end Kernel panic - not syncing: Kernel stack overflow ]---","state":0,"publishedAt":"2024-05-21T15:30:47.086+00:00","modifiedAt":"2026-08-05T09:11:17.032+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"unaffected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"arch/riscv/include/asm/asm-prototypes.h\",\n \"arch/riscv/include/asm/asm.h\",\n \"arch/riscv/include/asm/thread_info.h\",\n \"arch/riscv/kernel/asm-offsets.c\",\n \"arch/riscv/kernel/entry.S\",\n \"arch/riscv/kernel/traps.c\"\n ],\n \"versions\": [\n {\n \"version\": \"76d2a0493a17d4c8ecc781366850c3c4f8e1a446\",\n \"lessThan\": \"1493baaf09e3c1899959c8a107cd1207e16d1788\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"76d2a0493a17d4c8ecc781366850c3c4f8e1a446\",\n \"lessThan\": \"eff53aea3855f71992c043cebb1c00988c17ee20\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"76d2a0493a17d4c8ecc781366850c3c4f8e1a446\",\n \"lessThan\": \"be97d0db5f44c0674480cb79ac6f5b0529b84c76\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n }\n ]\n }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"affected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"arch/riscv/include/asm/asm-prototypes.h\",\n \"arch/riscv/include/asm/asm.h\",\n \"arch/riscv/include/asm/thread_info.h\",\n \"arch/riscv/kernel/asm-offsets.c\",\n \"arch/riscv/kernel/entry.S\",\n \"arch/riscv/kernel/traps.c\"\n ],\n \"versions\": [\n {\n \"version\": \"4.15\",\n \"status\": \"affected\"\n },\n {\n \"version\": \"0\",\n \"lessThan\": \"4.15\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.5.13\",\n \"lessThanOrEqual\": \"6.5.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.6.3\",\n \"lessThanOrEqual\": \"6.6.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.7\",\n \"lessThanOrEqual\": \"*\",\n \"status\": \"unaffected\",\n \"versionType\": \"original_commit_for_fix\"\n }\n ]\n }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/1493baaf09e3c1899959c8a107cd1207e16d1788","https://git.kernel.org/stable/c/eff53aea3855f71992c043cebb1c00988c17ee20","https://git.kernel.org/stable/c/be97d0db5f44c0674480cb79ac6f5b0529b84c76"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2023-52761","license":"CVE Program Terms of Use","key":"cve-program:CVE-2023-52761","identifiers":["CVE-2023-52761"]},"retained":false,"historicalAffected":[]}],"coverage":[]}