| { |
| "containers": { |
| "cna": { |
| "providerMetadata": { |
| "orgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038" |
| }, |
| "descriptions": [ |
| { |
| "lang": "en", |
| "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrcu/nocb: Fix missed RCU barrier on deoffloading\n\nCurrently, running rcutorture test with torture_type=rcu fwd_progress=8\nn_barrier_cbs=8 nocbs_nthreads=8 nocbs_toggle=100 onoff_interval=60\ntest_boost=2, will trigger the following warning:\n\n\tWARNING: CPU: 19 PID: 100 at kernel/rcu/tree_nocb.h:1061 rcu_nocb_rdp_deoffload+0x292/0x2a0\n\tRIP: 0010:rcu_nocb_rdp_deoffload+0x292/0x2a0\n\t Call Trace:\n\t <TASK>\n\t ? __warn+0x7e/0x120\n\t ? rcu_nocb_rdp_deoffload+0x292/0x2a0\n\t ? report_bug+0x18e/0x1a0\n\t ? handle_bug+0x3d/0x70\n\t ? exc_invalid_op+0x18/0x70\n\t ? asm_exc_invalid_op+0x1a/0x20\n\t ? rcu_nocb_rdp_deoffload+0x292/0x2a0\n\t rcu_nocb_cpu_deoffload+0x70/0xa0\n\t rcu_nocb_toggle+0x136/0x1c0\n\t ? __pfx_rcu_nocb_toggle+0x10/0x10\n\t kthread+0xd1/0x100\n\t ? __pfx_kthread+0x10/0x10\n\t ret_from_fork+0x2f/0x50\n\t ? __pfx_kthread+0x10/0x10\n\t ret_from_fork_asm+0x1a/0x30\n\t </TASK>\n\nCPU0 CPU2 CPU3\n//rcu_nocb_toggle //nocb_cb_wait //rcutorture\n\n// deoffload CPU1 // process CPU1's rdp\nrcu_barrier()\n rcu_segcblist_entrain()\n rcu_segcblist_add_len(1);\n // len == 2\n // enqueue barrier\n // callback to CPU1's\n // rdp->cblist\n rcu_do_batch()\n // invoke CPU1's rdp->cblist\n // callback\n rcu_barrier_callback()\n rcu_barrier()\n mutex_lock(&rcu_state.barrier_mutex);\n // still see len == 2\n // enqueue barrier callback\n // to CPU1's rdp->cblist\n rcu_segcblist_entrain()\n rcu_segcblist_add_len(1);\n // len == 3\n // decrement len\n rcu_segcblist_add_len(-2);\n kthread_parkme()\n\n// CPU1's rdp->cblist len == 1\n// Warn because there is\n// still a pending barrier\n// trigger warning\nWARN_ON_ONCE(rcu_segcblist_n_cbs(&rdp->cblist));\ncpus_read_unlock();\n\n // wait CPU1 to comes online and\n // invoke barrier callback on\n // CPU1 rdp's->cblist\n wait_for_completion(&rcu_state.barrier_completion);\n// deoffload CPU4\ncpus_read_lock()\n rcu_barrier()\n mutex_lock(&rcu_state.barrier_mutex);\n // block on barrier_mutex\n // wait rcu_barrier() on\n // CPU3 to unlock barrier_mutex\n // but CPU3 unlock barrier_mutex\n // need to wait CPU1 comes online\n // when CPU1 going online will block on cpus_write_lock\n\nThe above scenario will not only trigger a WARN_ON_ONCE(), but also\ntrigger a deadlock.\n\nThanks to nocb locking, a second racing rcu_barrier() on an offline CPU\nwill either observe the decremented callback counter down to 0 and spare\nthe callback enqueue, or rcuo will observe the new callback and keep\nrdp->nocb_cb_sleep to false.\n\nTherefore check rdp->nocb_cb_sleep before parking to make sure no\nfurther rcu_barrier() is waiting on the rdp." |
| } |
| ], |
| "affected": [ |
| { |
| "product": "Linux", |
| "vendor": "Linux", |
| "defaultStatus": "unaffected", |
| "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", |
| "programFiles": [ |
| "kernel/rcu/tree_nocb.h" |
| ], |
| "versions": [ |
| { |
| "version": "1fcb932c8b5ce86219d7dedcd63659351a43291c", |
| "lessThan": "224b62028959858294789772d372dcb36cf5f820", |
| "status": "affected", |
| "versionType": "git" |
| }, |
| { |
| "version": "1fcb932c8b5ce86219d7dedcd63659351a43291c", |
| "lessThan": "2996980e20b7a54a1869df15b3445374b850b155", |
| "status": "affected", |
| "versionType": "git" |
| } |
| ] |
| }, |
| { |
| "product": "Linux", |
| "vendor": "Linux", |
| "defaultStatus": "affected", |
| "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", |
| "programFiles": [ |
| "kernel/rcu/tree_nocb.h" |
| ], |
| "versions": [ |
| { |
| "version": "6.12", |
| "status": "affected" |
| }, |
| { |
| "version": "0", |
| "lessThan": "6.12", |
| "status": "unaffected", |
| "versionType": "semver" |
| }, |
| { |
| "version": "6.12.2", |
| "lessThanOrEqual": "6.12.*", |
| "status": "unaffected", |
| "versionType": "semver" |
| }, |
| { |
| "version": "6.13", |
| "lessThanOrEqual": "*", |
| "status": "unaffected", |
| "versionType": "original_commit_for_fix" |
| } |
| ] |
| } |
| ], |
| "cpeApplicability": [ |
| { |
| "nodes": [ |
| { |
| "operator": "OR", |
| "negate": false, |
| "cpeMatch": [ |
| { |
| "vulnerable": true, |
| "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", |
| "versionStartIncluding": "6.12", |
| "versionEndExcluding": "6.12.2" |
| }, |
| { |
| "vulnerable": true, |
| "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", |
| "versionStartIncluding": "6.12", |
| "versionEndExcluding": "6.13" |
| } |
| ] |
| } |
| ] |
| } |
| ], |
| "references": [ |
| { |
| "url": "https://git.kernel.org/stable/c/224b62028959858294789772d372dcb36cf5f820" |
| }, |
| { |
| "url": "https://git.kernel.org/stable/c/2996980e20b7a54a1869df15b3445374b850b155" |
| } |
| ], |
| "title": "rcu/nocb: Fix missed RCU barrier on deoffloading", |
| "x_generator": { |
| "engine": "bippy-1.2.0" |
| } |
| } |
| }, |
| "cveMetadata": { |
| "assignerOrgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038", |
| "cveID": "CVE-2024-56547", |
| "requesterUserId": "gregkh@kernel.org", |
| "serial": "1", |
| "state": "PUBLISHED" |
| }, |
| "dataType": "CVE_RECORD", |
| "dataVersion": "5.0" |
| } |
