{"id":"CVE-2026-90209","state":"PUBLISHED","title":"s390/debug: Fix deadlock during unregister","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ns390/debug: Fix deadlock during unregister\n\nUnregistering an s390dbf debug area while one of the associated debugfs\nfiles is being written to can cause a deadlock:\n\n$ echo >.../vmur/level    $ rmmod vmur\n===================================================\ndebugfs write\ndebugfs_file_get()\n                          debug_unregister()\n                          mutex_lock(debug_mutex)\n                          debugfs_remove()\n                          wait for debugfs_file_put()\ndebug_file_ops.write()\ndebug_input()\nmutex_lock(debug_mutex) ==> DEADLOCK\n\nFix this by splitting debug_unregister() into an s390dbf and debugfs\npart, and running only the s390dbf part with debug_mutex locked.","publishedAt":"2026-09-17T16:07:24.126Z","updatedAt":"2026-10-19T08:59:45.470Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"9372a82892c2caa6bccab9a4081166fa769699f8","status":"affected","lessThan":"a214c3dacc779b2afcb0ac9c8001e45ee4ffb2ed","versionType":"git"},{"version":"9372a82892c2caa6bccab9a4081166fa769699f8","status":"affected","lessThan":"183f8f6d64bb0510070c856b9927618c53014a7b","versionType":"git"},{"version":"9372a82892c2caa6bccab9a4081166fa769699f8","status":"affected","lessThan":"a08b70ed2d1ec907353a72f15163b8e34ff4b2f8","versionType":"git"},{"version":"9372a82892c2caa6bccab9a4081166fa769699f8","status":"affected","lessThan":"45bb341d1b73eb293e0dd43d9b72bbc8b615d0ba","versionType":"git"},{"version":"9372a82892c2caa6bccab9a4081166fa769699f8","status":"affected","lessThan":"5d83f3faa3fb7f23f298cfd40382611999de5d1d","versionType":"git"},{"version":"9372a82892c2caa6bccab9a4081166fa769699f8","status":"affected","lessThan":"54e1259b75d6402a1d0cfb822b9bb2c507e53dab","versionType":"git"},{"version":"9372a82892c2caa6bccab9a4081166fa769699f8","status":"affected","lessThan":"445c31ac638fd1af203d79bdf25fc0cb3149fbbc","versionType":"git"},{"version":"c68ba4a708fbd0efdc384cd29250bb292a45e559","status":"affected","versionType":"git"},{"version":"86f9980909f31ab205323eeeb290fe3cbb4952b4","status":"affected","versionType":"git"},{"version":"fe5793e90d3f572a87ba67fe2f0e1679fdff14f8","status":"affected","versionType":"git"},{"version":"e234f66168f0d50c0d28154fb983a14e85c3c526","status":"affected","versionType":"git"},{"version":"5.4.146","status":"affected","lessThan":"5.5","versionType":"semver"},{"version":"5.10.65","status":"affected","lessThan":"5.11","versionType":"semver"},{"version":"5.13.17","status":"affected","lessThan":"5.14","versionType":"semver"},{"version":"5.14.4","status":"affected","lessThan":"5.15","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/s390/kernel/debug.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.15","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.15","versionType":"semver"},{"version":"5.15.221","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.188","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.157","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.110","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.52","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.6","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/s390/kernel/debug.c"]}],"references":["https://git.kernel.org/stable/c/a214c3dacc779b2afcb0ac9c8001e45ee4ffb2ed","https://git.kernel.org/stable/c/183f8f6d64bb0510070c856b9927618c53014a7b","https://git.kernel.org/stable/c/a08b70ed2d1ec907353a72f15163b8e34ff4b2f8","https://git.kernel.org/stable/c/45bb341d1b73eb293e0dd43d9b72bbc8b615d0ba","https://git.kernel.org/stable/c/5d83f3faa3fb7f23f298cfd40382611999de5d1d","https://git.kernel.org/stable/c/54e1259b75d6402a1d0cfb822b9bb2c507e53dab","https://git.kernel.org/stable/c/445c31ac638fd1af203d79bdf25fc0cb3149fbbc"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:34.582Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/90xxx/CVE-2026-90209.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-90209","state":"PUBLISHED","datePublished":"2026-09-17T16:07:24.126Z","dateUpdated":"2026-10-19T08:59:45.470Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-11T19:38:34.793Z"},"containers":{"cna":{"title":"s390/debug: Fix deadlock during unregister","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ns390/debug: Fix deadlock during unregister\n\nUnregistering an s390dbf debug area while one of the associated debugfs\nfiles is being written to can cause a deadlock:\n\n$ echo >.../vmur/level    $ rmmod vmur\n===================================================\ndebugfs write\ndebugfs_file_get()\n                          debug_unregister()\n                          mutex_lock(debug_mutex)\n                          debugfs_remove()\n                          wait for debugfs_file_put()\ndebug_file_ops.write()\ndebug_input()\nmutex_lock(debug_mutex) ==> DEADLOCK\n\nFix this by splitting debug_unregister() into an s390dbf and debugfs\npart, and running only the s390dbf part with debug_mutex locked."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"9372a82892c2caa6bccab9a4081166fa769699f8","status":"affected","lessThan":"a214c3dacc779b2afcb0ac9c8001e45ee4ffb2ed","versionType":"git"},{"version":"9372a82892c2caa6bccab9a4081166fa769699f8","status":"affected","lessThan":"183f8f6d64bb0510070c856b9927618c53014a7b","versionType":"git"},{"version":"9372a82892c2caa6bccab9a4081166fa769699f8","status":"affected","lessThan":"a08b70ed2d1ec907353a72f15163b8e34ff4b2f8","versionType":"git"},{"version":"9372a82892c2caa6bccab9a4081166fa769699f8","status":"affected","lessThan":"45bb341d1b73eb293e0dd43d9b72bbc8b615d0ba","versionType":"git"},{"version":"9372a82892c2caa6bccab9a4081166fa769699f8","status":"affected","lessThan":"5d83f3faa3fb7f23f298cfd40382611999de5d1d","versionType":"git"},{"version":"9372a82892c2caa6bccab9a4081166fa769699f8","status":"affected","lessThan":"54e1259b75d6402a1d0cfb822b9bb2c507e53dab","versionType":"git"},{"version":"9372a82892c2caa6bccab9a4081166fa769699f8","status":"affected","lessThan":"445c31ac638fd1af203d79bdf25fc0cb3149fbbc","versionType":"git"},{"version":"c68ba4a708fbd0efdc384cd29250bb292a45e559","status":"affected","versionType":"git"},{"version":"86f9980909f31ab205323eeeb290fe3cbb4952b4","status":"affected","versionType":"git"},{"version":"fe5793e90d3f572a87ba67fe2f0e1679fdff14f8","status":"affected","versionType":"git"},{"version":"e234f66168f0d50c0d28154fb983a14e85c3c526","status":"affected","versionType":"git"},{"version":"5.4.146","status":"affected","lessThan":"5.5","versionType":"semver"},{"version":"5.10.65","status":"affected","lessThan":"5.11","versionType":"semver"},{"version":"5.13.17","status":"affected","lessThan":"5.14","versionType":"semver"},{"version":"5.14.4","status":"affected","lessThan":"5.15","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/s390/kernel/debug.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.15","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.15","versionType":"semver"},{"version":"5.15.221","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.188","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.157","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.110","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.52","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.6","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/s390/kernel/debug.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/a214c3dacc779b2afcb0ac9c8001e45ee4ffb2ed"},{"url":"https://git.kernel.org/stable/c/183f8f6d64bb0510070c856b9927618c53014a7b"},{"url":"https://git.kernel.org/stable/c/a08b70ed2d1ec907353a72f15163b8e34ff4b2f8"},{"url":"https://git.kernel.org/stable/c/45bb341d1b73eb293e0dd43d9b72bbc8b615d0ba"},{"url":"https://git.kernel.org/stable/c/5d83f3faa3fb7f23f298cfd40382611999de5d1d"},{"url":"https://git.kernel.org/stable/c/54e1259b75d6402a1d0cfb822b9bb2c507e53dab"},{"url":"https://git.kernel.org/stable/c/445c31ac638fd1af203d79bdf25fc0cb3149fbbc"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T08:59:45.470Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"5.15.221"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.1.188"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.6.157"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.12.110"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.18.52"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"7.2.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"7.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.4.146"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10.65"},{"vulnerable":true,"criteria":"cpe:2.3:o:lin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