I got this null-ptr-deref report while doing fuzz test:
[ 158.820284][T12735] BUG: KASAN: null-ptr-deref in dma_pool_create+0xf7/0x440 [ 158.821192][T12735] Read of size 4 at addr 0000000000000298 by task syz-executor.7/12735 [ 158.822239][T12735] [ 158.822539][T12735] CPU: 0 PID: 12735 Comm: syz-executor.7 Not tainted 5.10.78 #691 [ 158.823494][T12735] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 [ 158.824720][T12735] Call Trace: [ 158.825889][T12735] dump_stack+0x111/0x151 [ 158.826458][T12735] ? dma_pool_create+0xf7/0x440 [ 158.827067][T12735] ? dma_pool_create+0xf7/0x440 [ 158.827672][T12735] kasan_report.cold.11+0x5/0x37 [ 158.828289][T12735] ? dma_pool_create+0xf7/0x440 [ 158.828894][T12735] dma_pool_create+0xf7/0x440 [ 158.829480][T12735] rds_ib_add_one+0x448/0x570 [ 158.830062][T12735] ? rds_ib_remove_one+0x150/0x150 [ 158.830702][T12735] add_client_context+0x2ef/0x440 [ 158.831329][T12735] ? ib_unregister_driver+0x1a0/0x1a0 [ 158.832005][T12735] ? strchr+0x28/0x50 [ 158.832527][T12735] enable_device_and_get+0x199/0x320 [ 158.833194][T12735] ? add_one_compat_dev.part.20+0x3d0/0x3d0 [ 158.833924][T12735] ? rxe_ib_alloc_hw_stats+0x84/0x90 [ 158.834590][T12735] ? setup_hw_stats+0x40/0x520 [ 158.835184][T12735] ? uevent_show+0x1e0/0x1e0 [ 158.835758][T12735] ? rxe_ib_get_hw_stats+0xa0/0xa0 [ 158.836398][T12735] ib_register_device+0x8ef/0x9d0 [ 158.837026][T12735] ? netlink_unicast+0x3e1/0x510 [ 158.837644][T12735] ? alloc_port_data.part.17+0x1f0/0x1f0 [ 158.838358][T12735] ? __alloc_pages_nodemask+0x229/0x450 [ 158.839051][T12735] ? kasan_unpoison_shadow+0x30/0x40 [ 158.839710][T12735] ? __kasan_kmalloc.constprop.12+0xbe/0xd0 [ 158.840443][T12735] ? kmem_cache_alloc_node_trace+0xa3/0x870 [ 158.841178][T12735] ? __crypto_alg_lookup+0x26d/0x2d0 [ 158.841841][T12735] ? __kasan_kmalloc.constprop.12+0xbe/0xd0 [ 158.842573][T12735] ? crypto_shash_init_tfm+0x10d/0x160 [ 158.843255][T12735] ? crc32_pclmul_cra_init+0x12/0x20 [ 158.843916][T12735] ? crypto_create_tfm_node+0xb7/0x1a0 [ 158.844594][T12735] ? crypto_alloc_tfm_node+0x12e/0x260 [ 158.845273][T12735] rxe_register_device+0x21f/0x250 [ 158.845904][T12735] rxe_add+0x9f9/0xa80 [ 158.846412][T12735] rxe_net_add+0x56/0xa0 [ 158.846917][T12735] rxe_newlink+0x8c/0xb0 [ 158.847427][T12735] nldev_newlink+0x23d/0x360 [ 158.847973][T12735] ? nldev_set_doit+0x2b0/0x2b0 [ 158.848562][T12735] ? apparmor_capable+0x2e9/0x4e0 [ 158.849159][T12735] ? apparmor_cred_prepare+0x3f0/0x3f0 [ 158.849811][T12735] ? apparmor_cred_prepare+0x3f0/0x3f0 [ 158.850469][T12735] ? ____sys_sendmsg+0x4db/0x500 [ 158.851064][T12735] ? ___sys_sendmsg+0xf8/0x160 [ 158.851648][T12735] ? entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 158.852400][T12735] ? cap_capable+0x125/0x140 [ 158.854398][T12735] ? ns_capable_common+0x88/0xa0 [ 158.855012][T12735] ? nldev_set_doit+0x2b0/0x2b0 [ 158.855611][T12735] rdma_nl_rcv+0x41f/0x630 [ 158.856162][T12735] ? rdma_nl_multicast+0xa0/0xa0 [ 158.856772][T12735] ? netlink_lookup+0x273/0x3a0 [ 158.857374][T12735] ? netlink_broadcast+0x40/0x40 [ 158.857984][T12735] ? __kasan_kmalloc.constprop.12+0xbe/0xd0 [ 158.858724][T12735] ? __rcu_read_unlock+0x34/0x260 [ 158.859349][T12735] ? netlink_deliver_tap+0x65/0x450 [ 158.859991][T12735] netlink_unicast+0x3e1/0x510 [ 158.860586][T12735] ? netlink_attachskb+0x540/0x540 [ 158.861218][T12735] ? _copy_from_iter_full+0x1b9/0x5e0 [ 158.861905][T12735] ? __check_object_size+0x27c/0x300 [ 158.862561][T12735] netlink_sendmsg+0x4aa/0x870 [ 158.863131][T12735] ? netlink_unicast+0x510/0x510 [ 158.863728][T12735] ? netlink_unicast+0x510/0x510 [ 158.864326][T12735] sock_sendmsg+0x83/0xa0 [ 158.864849][T12735] ____sys_sendmsg+0x4db/0x500 [ 158.865429][T12735] ? __copy_msghdr_from_user+0x310/0x310 [ 158.866112][T12735] ? kernel_sendmsg+0x50/0x50 [ 158.866700][T12735] ? do_syscall_64+0x2d/0x70 [ 158.867256][T12735] ? entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 158.867996][T12735] ___sys_sendmsg+0xf8/0x160 [ 158.868552][T12735] ? sendmsg_copy_msghdr+0x70/0x70 [ 158.869175][T12735] ? kasan_unpoison_shadow+0x30/0x40 [ 158.869824][T12735] ? futex_exit_release+0x80/0x80 [ 158.870442][T12735] ? apparmor_task_setrlimit+0x500/0x500 [ 158.871122][T12735] ? kmem_cache_alloc+0x143/0x810 [ 158.871733][T12735] ? __rcu_read_unlock+0x34/0x260 [ 158.872351][T12735] ? __fget_files+0x14a/0x1b0 [ 158.872920][T12735] ? __fget_light+0xeb/0x140 [ 158.873474][T12735] __sys_sendmsg+0xfe/0x1c0 [ 158.874017][T12735] ? __sys_sendmsg_sock+0x80/0x80 [ 158.874625][T12735] ? _copy_to_user+0x97/0xb0 [ 158.875177][T12735] ? put_timespec64+0xab/0xe0 [ 158.875740][T12735] ? nsecs_to_jiffies+0x30/0x30 [ 158.876325][T12735] ? fpregs_assert_state_consistent+0x8f/0xa0 [ 158.877054][T12735] do_syscall_64+0x2d/0x70 [ 158.877585][T12735] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 158.878297][T12735] RIP: 0033:0x45ecc9 [ 158.878769][T12735] Code: 1d b1 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 eb b0 fb ff c3 66 2e 0f 1f 84 00 00 00 00 [ 158.881085][T12735] RSP: 002b:00007f2c7a09fc68 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 158.882086][T12735] RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045ecc9 [ 158.883038][T12735] RDX: 0000000000000000 RSI: 00000000200001c0 RDI: 000000000000000a [ 158.883983][T12735] RBP: 000000000119bfe0 R08: 0000000000000000 R09: 0000000000000000 [ 158.884929][T12735] R10: 0000000000000000 R11: 0000000000000246 R12: 000000000119bfac [ 158.885877][T12735] R13: 00007fff86afff9f R14: 00007f2c7a0a09c0 R15: 000000000119bfac
In rxe_register_device(), it passes a null pointer to ib_register_device() the 'device->dma_device' will be set to null, when it used in rds_ib_add_one(), it leads a null-ptr-deref.
Christoph Hellwig (1): rds: stop using dmapool
net/rds/ib.c | 10 ---- net/rds/ib.h | 6 --- net/rds/ib_cm.c | 128 ++++++++++++++++++++++++++++------------------ net/rds/ib_recv.c | 18 +++++-- net/rds/ib_send.c | 8 +++ 5 files changed, 101 insertions(+), 69 deletions(-)