In the Linux kernel, the following vulnerability has been resolved: RDMA/core: Fix use after free in ib_query_qp() When querying a QP via the netlin...

In the Linux kernel, the following vulnerability has been resolved: RDMA/core: Fix use after free in ib_query_qp() When querying a QP via the netlink flow the only synchronization mechanism for the said QP is rdma_restrack_get(), meanwhile during the QP destroy path rdma_restrack_del() is called at the end of the ib_destroy_qp_user() function which is too late, since by then the vendor specific resources for said QP would already be destroyed, and till the rdma_restrack_del() is called this QP can still be accessed, which could cause the use after free below. Fix this by moving the rdma_restrack_begin_del() to the start of the ib_destroy_qp_user(), which in turn waits for all usages of the QP to be done then removes it from the database to prevent access to it while it is being destroyed. RIP: 0010:ib_query_qp+0x15/0x50 [ib_core] Code: 48 83 05 5d 8e b9 ff 01 eb b5 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 c7 46 40 00 00 00 00 48 c7 46 78 00 00 00 00 <48> 8b 07 48 8b 80 88 01 00 00 48 85 c0 74 1a 48 83 05 54 91 b9 ff RSP: 0018:ff11000108a8f2f0 EFLAGS: 00010202 RAX: 0000000000000000 RBX: ff11000108a8f370 RCX: ff11000108a8f370 RDX: 0000000000000000 RSI: ff11000108a8f3d8 RDI: 0000000000000000 RBP: ff1100010de5a000 R08: 0000000000000e80 R09: 0000000000000004 R10: ff110001057a604c R11: 0000000000000000 R12: ff11000108a8f370 R13: ff110001090e8000 R14: 0000000000000000 R15: ff110001057a602c FS: 00007f2ffd8db6c0(0000) GS:ff110008dc90b000(0000) knlGS:0000000000000000 CS:…