In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applicationsThere is no fixed version for Centos:7
perf
.
Note: Versions mentioned in the description apply only to the upstream perf
package and not the perf
package as distributed by Centos
.
See How to fix?
for Centos:7
relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
nfsd: decrease sc_count directly if fail to queue dl_recall
A deadlock warning occurred when invoking nfs4_put_stid following a failed dl_recall queue operation: T1 T2 nfs4_laundromat nfs4_get_client_reaplist nfs4_anylock_blockers __break_lease spin_lock // ctx->flc_lock spin_lock // clp->cl_lock nfs4_lockowner_has_blockers locks_owner_has_blockers spin_lock // flctx->flc_lock nfsd_break_deleg_cb nfsd_break_one_deleg nfs4_put_stid refcount_dec_and_lock spin_lock // clp->cl_lock
When a file is opened, an nfs4_delegation is allocated with sc_count initialized to 1, and the file_lease holds a reference to the delegation. The file_lease is then associated with the file through kernel_setlease.
The disassociation is performed in nfsd4_delegreturn via the following call chain: nfsd4_delegreturn --> destroy_delegation --> destroy_unhashed_deleg --> nfs4_unlock_deleg_lease --> kernel_setlease --> generic_delete_lease The corresponding sc_count reference will be released after this disassociation.
Since nfsd_break_one_deleg executes while holding the flc_lock, the disassociation process becomes blocked when attempting to acquire flc_lock in generic_delete_lease. This means:
Given that sc_count in nfsd_break_one_deleg remains non-zero, we can safely perform refcount_dec on sc_count directly. This approach effectively avoids triggering deadlock warnings.