{"id":"CVE-2023-53668","state":"PUBLISHED","title":"ring-buffer: Fix deadloop issue on reading trace_pipe","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nring-buffer: Fix deadloop issue on reading trace_pipe\n\nSoft lockup occurs when reading file 'trace_pipe':\n\n  watchdog: BUG: soft lockup - CPU#6 stuck for 22s! [cat:4488]\n  [...]\n  RIP: 0010:ring_buffer_empty_cpu+0xed/0x170\n  RSP: 0018:ffff88810dd6fc48 EFLAGS: 00000246\n  RAX: 0000000000000000 RBX: 0000000000000246 RCX: ffffffff93d1aaeb\n  RDX: ffff88810a280040 RSI: 0000000000000008 RDI: ffff88811164b218\n  RBP: ffff88811164b218 R08: 0000000000000000 R09: ffff88815156600f\n  R10: ffffed102a2acc01 R11: 0000000000000001 R12: 0000000051651901\n  R13: 0000000000000000 R14: ffff888115e49500 R15: 0000000000000000\n  [...]\n  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n  CR2: 00007f8d853c2000 CR3: 000000010dcd8000 CR4: 00000000000006e0\n  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\n  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\n  Call Trace:\n   __find_next_entry+0x1a8/0x4b0\n   ? peek_next_entry+0x250/0x250\n   ? down_write+0xa5/0x120\n   ? down_write_killable+0x130/0x130\n   trace_find_next_entry_inc+0x3b/0x1d0\n   tracing_read_pipe+0x423/0xae0\n   ? tracing_splice_read_pipe+0xcb0/0xcb0\n   vfs_read+0x16b/0x490\n   ksys_read+0x105/0x210\n   ? __ia32_sys_pwrite64+0x200/0x200\n   ? switch_fpu_return+0x108/0x220\n   do_syscall_64+0x33/0x40\n   entry_SYSCALL_64_after_hwframe+0x61/0xc6\n\nThrough the vmcore, I found it's because in tracing_read_pipe(),\nring_buffer_empty_cpu() found some buffer is not empty but then it\ncannot read anything due to \"rb_num_of_entries() == 0\" always true,\nThen it infinitely loop the procedure due to user buffer not been\nfilled, see following code path:\n\n  tracing_read_pipe() {\n    ... ...\n    waitagain:\n      tracing_wait_pipe() // 1. find non-empty buffer here\n      trace_find_next_entry_inc()  // 2. loop here try to find an entry\n        __find_next_entry()\n          ring_buffer_empty_cpu();  // 3. find non-empty buffer\n          peek_next_entry()  // 4. but peek always return NULL\n            ring_buffer_peek()\n              rb_buffer_peek()\n                rb_get_reader_page()\n                  // 5. because rb_num_of_entries() == 0 always true here\n                  //    then return NULL\n      // 6. user buffer not been filled so goto 'waitgain'\n      //    and eventually leads to an deadloop in kernel!!!\n  }\n\nBy some analyzing, I found that when resetting ringbuffer, the 'entries'\nof its pages are not all cleared (see rb_reset_cpu()). Then when reducing\nthe ringbuffer, and if some reduced pages exist dirty 'entries' data, they\nwill be added into 'cpu_buffer->overrun' (see rb_remove_pages()), which\ncause wrong 'overrun' count and eventually cause the deadloop issue.\n\nTo fix it, we need to clear every pages in rb_reset_cpu().","publishedAt":"2025-10-07T15:21:26.164Z","updatedAt":"2026-05-11T19:49:36.478Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"a5fb833172eca69136e9ee1ada778e404086ab8a","status":"affected","lessThan":"0a29dae5786d263016a9aceb1e56bf3fd4cc6fa0","versionType":"git"},{"version":"a5fb833172eca69136e9ee1ada778e404086ab8a","status":"affected","lessThan":"a55e8a3596048c2f7b574049aeb1885b5abba1cc","versionType":"git"},{"version":"a5fb833172eca69136e9ee1ada778e404086ab8a","status":"affected","lessThan":"e84829522fc72bb43556b31575731de0440ac0dd","versionType":"git"},{"version":"a5fb833172eca69136e9ee1ada778e404086ab8a","status":"affected","lessThan":"5e68f1f3a20fe9b6bde018e353269fbfa289609c","versionType":"git"},{"version":"a5fb833172eca69136e9ee1ada778e404086ab8a","status":"affected","lessThan":"bb14a93bccc92766b1d9302c6bcbea17d4bce306","versionType":"git"},{"version":"a5fb833172eca69136e9ee1ada778e404086ab8a","status":"affected","lessThan":"8b0b63fdac6b70a45614e7d4b30e5bbb93deb007","versionType":"git"},{"version":"a5fb833172eca69136e9ee1ada778e404086ab8a","status":"affected","lessThan":"27bdd93e44cc28dd9b94893fae146b83d4f5b31e","versionType":"git"},{"version":"a5fb833172eca69136e9ee1ada778e404086ab8a","status":"affected","lessThan":"7e42907f3a7b4ce3a2d1757f6d78336984daf8f5","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/trace/ring_buffer.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.6","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.6","versionType":"semver"},{"version":"4.14.322","status":"unaffected","lessThanOrEqual":"4.14.*","versionType":"semver"},{"version":"4.19.291","status":"unaffected","lessThanOrEqual":"4.19.*","versionType":"semver"},{"version":"5.4.251","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.188","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.121","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.40","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.4.5","status":"unaffected","lessThanOrEqual":"6.4.*","versionType":"semver"},{"version":"6.5","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/trace/ring_buffer.c"]}],"references":["https://git.kernel.org/stable/c/0a29dae5786d263016a9aceb1e56bf3fd4cc6fa0","https://git.kernel.org/stable/c/a55e8a3596048c2f7b574049aeb1885b5abba1cc","https://git.kernel.org/stable/c/e84829522fc72bb43556b31575731de0440ac0dd","https://git.kernel.org/stable/c/5e68f1f3a20fe9b6bde018e353269fbfa289609c","https://git.kernel.org/stable/c/bb14a93bccc92766b1d9302c6bcbea17d4bce306","https://git.kernel.org/stable/c/8b0b63fdac6b70a45614e7d4b30e5bbb93deb007","https://git.kernel.org/stable/c/27bdd93e44cc28dd9b94893fae146b83d4f5b31e","https://git.kernel.org/stable/c/7e42907f3a7b4ce3a2d1757f6d78336984daf8f5"],"weaknesses":[],"ingestedAt":"2026-10-29T20:06:33.064Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2023/53xxx/CVE-2023-53668.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2023-53668","state":"PUBLISHED","datePublished":"2025-10-07T15:21:26.164Z","dateUpdated":"2026-05-11T19:49:36.478Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-10-07T15:16:59.663Z"},"containers":{"cna":{"title":"ring-buffer: Fix deadloop issue on reading trace_pipe","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nring-buffer: Fix deadloop issue on reading trace_pipe\n\nSoft lockup occurs when reading file 'trace_pipe':\n\n  watchdog: BUG: soft lockup - CPU#6 stuck for 22s! [cat:4488]\n  [...]\n  RIP: 0010:ring_buffer_empty_cpu+0xed/0x170\n  RSP: 0018:ffff88810dd6fc48 EFLAGS: 00000246\n  RAX: 0000000000000000 RBX: 0000000000000246 RCX: ffffffff93d1aaeb\n  RDX: ffff88810a280040 RSI: 0000000000000008 RDI: ffff88811164b218\n  RBP: ffff88811164b218 R08: 0000000000000000 R09: ffff88815156600f\n  R10: ffffed102a2acc01 R11: 0000000000000001 R12: 0000000051651901\n  R13: 0000000000000000 R14: ffff888115e49500 R15: 0000000000000000\n  [...]\n  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n  CR2: 00007f8d853c2000 CR3: 000000010dcd8000 CR4: 00000000000006e0\n  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\n  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\n  Call Trace:\n   __find_next_entry+0x1a8/0x4b0\n   ? peek_next_entry+0x250/0x250\n   ? down_write+0xa5/0x120\n   ? down_write_killable+0x130/0x130\n   trace_find_next_entry_inc+0x3b/0x1d0\n   tracing_read_pipe+0x423/0xae0\n   ? tracing_splice_read_pipe+0xcb0/0xcb0\n   vfs_read+0x16b/0x490\n   ksys_read+0x105/0x210\n   ? __ia32_sys_pwrite64+0x200/0x200\n   ? switch_fpu_return+0x108/0x220\n   do_syscall_64+0x33/0x40\n   entry_SYSCALL_64_after_hwframe+0x61/0xc6\n\nThrough the vmcore, I found it's because in tracing_read_pipe(),\nring_buffer_empty_cpu() found some buffer is not empty but then it\ncannot read anything due to \"rb_num_of_entries() == 0\" always true,\nThen it infinitely loop the procedure due to user buffer not been\nfilled, see following code path:\n\n  tracing_read_pipe() {\n    ... ...\n    waitagain:\n      tracing_wait_pipe() // 1. find non-empty buffer here\n      trace_find_next_entry_inc()  // 2. loop here try to find an entry\n        __find_next_entry()\n          ring_buffer_empty_cpu();  // 3. find non-empty buffer\n          peek_next_entry()  // 4. but peek always return NULL\n            ring_buffer_peek()\n              rb_buffer_peek()\n                rb_get_reader_page()\n                  // 5. because rb_num_of_entries() == 0 always true here\n                  //    then return NULL\n      // 6. user buffer not been filled so goto 'waitgain'\n      //    and eventually leads to an deadloop in kernel!!!\n  }\n\nBy some analyzing, I found that when resetting ringbuffer, the 'entries'\nof its pages are not all cleared (see rb_reset_cpu()). Then when reducing\nthe ringbuffer, and if some reduced pages exist dirty 'entries' data, they\nwill be added into 'cpu_buffer->overrun' (see rb_remove_pages()), which\ncause wrong 'overrun' count and eventually cause the deadloop issue.\n\nTo fix it, we need to clear every pages in rb_reset_cpu()."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"a5fb833172eca69136e9ee1ada778e404086ab8a","status":"affected","lessThan":"0a29dae5786d263016a9aceb1e56bf3fd4cc6fa0","versionType":"git"},{"version":"a5fb833172eca69136e9ee1ada778e404086ab8a","status":"affected","lessThan":"a55e8a3596048c2f7b574049aeb1885b5abba1cc","versionType":"git"},{"version":"a5fb833172eca69136e9ee1ada778e404086ab8a","status":"affected","lessThan":"e84829522fc72bb43556b31575731de0440ac0dd","versionType":"git"},{"version":"a5fb833172eca69136e9ee1ada778e404086ab8a","status":"affected","lessThan":"5e68f1f3a20fe9b6bde018e353269fbfa289609c","versionType":"git"},{"version":"a5fb833172eca69136e9ee1ada778e404086ab8a","status":"affected","lessThan":"bb14a93bccc92766b1d9302c6bcbea17d4bce306","versionType":"git"},{"version":"a5fb833172eca69136e9ee1ada778e404086ab8a","status":"affected","lessThan":"8b0b63fdac6b70a45614e7d4b30e5bbb93deb007","versionType":"git"},{"version":"a5fb833172eca69136e9ee1ada778e404086ab8a","status":"affected","lessThan":"27bdd93e44cc28dd9b94893fae146b83d4f5b31e","versionType":"git"},{"version":"a5fb833172eca69136e9ee1ada778e404086ab8a","status":"affected","lessThan":"7e42907f3a7b4ce3a2d1757f6d78336984daf8f5","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/trace/ring_buffer.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.6","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.6","versionType":"semver"},{"version":"4.14.322","status":"unaffected","lessThanOrEqual":"4.14.*","versionType":"semver"},{"version":"4.19.291","status":"unaffected","lessThanOrEqual":"4.19.*","versionType":"semver"},{"version":"5.4.251","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.188","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.121","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.40","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.4.5","status":"unaffected","lessThanOrEqual":"6.4.*","versionType":"semver"},{"version":"6.5","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/trace/ring_buffer.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/0a29dae5786d263016a9aceb1e56bf3fd4cc6fa0"},{"url":"https://git.kernel.org/stable/c/a55e8a3596048c2f7b574049aeb1885b5abba1cc"},{"url":"https://git.kernel.org/stable/c/e84829522fc72bb43556b31575731de0440ac0dd"},{"url":"https://git.kernel.org/stable/c/5e68f1f3a20fe9b6bde018e353269fbfa289609c"},{"url":"https://git.kernel.org/stable/c/bb14a93bccc92766b1d9302c6bcbea17d4bce306"},{"url":"https://git.kernel.org/stable/c/8b0b63fdac6b70a45614e7d4b30e5bbb93deb007"},{"url":"https://git.kernel.org/stable/c/27bdd93e44cc28dd9b94893fae146b83d4f5b31e"},{"url":"https://git.kernel.org/stable/c/7e42907f3a7b4ce3a2d1757f6d78336984daf8f5"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-05-11T19:49:36.478Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.6","versionEndExcluding":"4.14.322"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.6","versionEndExcluding":"4.19.291"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.6","versionEndExcluding":"5.4.251"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.6","versionEndExcluding":"5.10.188"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.6","versionEndExcluding":"5.15.121"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.6","versionEndExcluding":"6.1.40"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.6","versionEndExcluding":"6.4.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.6","versionEndExcluding":"6.5"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}