From: Tariq Toukan tariqt@nvidia.com
[ Upstream commit bacd22df95147ed673bec4692ab2d4d585935241 ]
mlx5_cmd_cleanup_async_ctx should return only after all its callback handlers were completed. Before this patch, the below race between mlx5_cmd_cleanup_async_ctx and mlx5_cmd_exec_cb_handler was possible and lead to a use-after-free:
1. mlx5_cmd_cleanup_async_ctx is called while num_inflight is 2 (i.e. elevated by 1, a single inflight callback). 2. mlx5_cmd_cleanup_async_ctx decreases num_inflight to 1. 3. mlx5_cmd_exec_cb_handler is called, decreases num_inflight to 0 and is about to call wake_up(). 4. mlx5_cmd_cleanup_async_ctx calls wait_event, which returns immediately as the condition (num_inflight == 0) holds. 5. mlx5_cmd_cleanup_async_ctx returns. 6. The caller of mlx5_cmd_cleanup_async_ctx frees the mlx5_async_ctx object. 7. mlx5_cmd_exec_cb_handler goes on and calls wake_up() on the freed object.
Fix it by syncing using a completion object. Mark it completed when num_inflight reaches 0.
Trace:
BUG: KASAN: use-after-free in do_raw_spin_lock+0x23d/0x270 Read of size 4 at addr ffff888139cd12f4 by task swapper/5/0
CPU: 5 PID: 0 Comm: swapper/5 Not tainted 6.0.0-rc3_for_upstream_debug_2022_08_30_13_10 #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 Call Trace: <IRQ> dump_stack_lvl+0x57/0x7d print_report.cold+0x2d5/0x684 ? do_raw_spin_lock+0x23d/0x270 kasan_report+0xb1/0x1a0 ? do_raw_spin_lock+0x23d/0x270 do_raw_spin_lock+0x23d/0x270 ? rwlock_bug.part.0+0x90/0x90 ? __delete_object+0xb8/0x100 ? lock_downgrade+0x6e0/0x6e0 _raw_spin_lock_irqsave+0x43/0x60 ? __wake_up_common_lock+0xb9/0x140 __wake_up_common_lock+0xb9/0x140 ? __wake_up_common+0x650/0x650 ? destroy_tis_callback+0x53/0x70 [mlx5_core] ? kasan_set_track+0x21/0x30 ? destroy_tis_callback+0x53/0x70 [mlx5_core] ? kfree+0x1ba/0x520 ? do_raw_spin_unlock+0x54/0x220 mlx5_cmd_exec_cb_handler+0x136/0x1a0 [mlx5_core] ? mlx5_cmd_cleanup_async_ctx+0x220/0x220 [mlx5_core] ? mlx5_cmd_cleanup_async_ctx+0x220/0x220 [mlx5_core] mlx5_cmd_comp_handler+0x65a/0x12b0 [mlx5_core] ? dump_command+0xcc0/0xcc0 [mlx5_core] ? lockdep_hardirqs_on_prepare+0x400/0x400 ? cmd_comp_notifier+0x7e/0xb0 [mlx5_core] cmd_comp_notifier+0x7e/0xb0 [mlx5_core] atomic_notifier_call_chain+0xd7/0x1d0 mlx5_eq_async_int+0x3ce/0xa20 [mlx5_core] atomic_notifier_call_chain+0xd7/0x1d0 ? irq_release+0x140/0x140 [mlx5_core] irq_int_handler+0x19/0x30 [mlx5_core] __handle_irq_event_percpu+0x1f2/0x620 handle_irq_event+0xb2/0x1d0 handle_edge_irq+0x21e/0xb00 __common_interrupt+0x79/0x1a0 common_interrupt+0x78/0xa0 </IRQ> <TASK> asm_common_interrupt+0x22/0x40 RIP: 0010:default_idle+0x42/0x60 Code: c1 83 e0 07 48 c1 e9 03 83 c0 03 0f b6 14 11 38 d0 7c 04 84 d2 75 14 8b 05 eb 47 22 02 85 c0 7e 07 0f 00 2d e0 9f 48 00 fb f4 <c3> 48 c7 c7 80 08 7f 85 e8 d1 d3 3e fe eb de 66 66 2e 0f 1f 84 00 RSP: 0018:ffff888100dbfdf0 EFLAGS: 00000242 RAX: 0000000000000001 RBX: ffffffff84ecbd48 RCX: 1ffffffff0afe110 RDX: 0000000000000004 RSI: 0000000000000000 RDI: ffffffff835cc9bc RBP: 0000000000000005 R08: 0000000000000001 R09: ffff88881dec4ac3 R10: ffffed1103bd8958 R11: 0000017d0ca571c9 R12: 0000000000000005 R13: ffffffff84f024e0 R14: 0000000000000000 R15: dffffc0000000000 ? default_idle_call+0xcc/0x450 default_idle_call+0xec/0x450 do_idle+0x394/0x450 ? arch_cpu_idle_exit+0x40/0x40 ? do_idle+0x17/0x450 cpu_startup_entry+0x19/0x20 start_secondary+0x221/0x2b0 ? set_cpu_sibling_map+0x2070/0x2070 secondary_startup_64_no_verify+0xcd/0xdb </TASK>
Allocated by task 49502: kasan_save_stack+0x1e/0x40 __kasan_kmalloc+0x81/0xa0 kvmalloc_node+0x48/0xe0 mlx5e_bulk_async_init+0x35/0x110 [mlx5_core] mlx5e_tls_priv_tx_list_cleanup+0x84/0x3e0 [mlx5_core] mlx5e_ktls_cleanup_tx+0x38f/0x760 [mlx5_core] mlx5e_cleanup_nic_tx+0xa7/0x100 [mlx5_core] mlx5e_detach_netdev+0x1ca/0x2b0 [mlx5_core] mlx5e_suspend+0xdb/0x140 [mlx5_core] mlx5e_remove+0x89/0x190 [mlx5_core] auxiliary_bus_remove+0x52/0x70 device_release_driver_internal+0x40f/0x650 driver_detach+0xc1/0x180 bus_remove_driver+0x125/0x2f0 auxiliary_driver_unregister+0x16/0x50 mlx5e_cleanup+0x26/0x30 [mlx5_core] cleanup+0xc/0x4e [mlx5_core] __x64_sys_delete_module+0x2b5/0x450 do_syscall_64+0x3d/0x90 entry_SYSCALL_64_after_hwframe+0x46/0xb0
Freed by task 49502: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 kasan_set_free_info+0x20/0x30 ____kasan_slab_free+0x11d/0x1b0 kfree+0x1ba/0x520 mlx5e_tls_priv_tx_list_cleanup+0x2e7/0x3e0 [mlx5_core] mlx5e_ktls_cleanup_tx+0x38f/0x760 [mlx5_core] mlx5e_cleanup_nic_tx+0xa7/0x100 [mlx5_core] mlx5e_detach_netdev+0x1ca/0x2b0 [mlx5_core] mlx5e_suspend+0xdb/0x140 [mlx5_core] mlx5e_remove+0x89/0x190 [mlx5_core] auxiliary_bus_remove+0x52/0x70 device_release_driver_internal+0x40f/0x650 driver_detach+0xc1/0x180 bus_remove_driver+0x125/0x2f0 auxiliary_driver_unregister+0x16/0x50 mlx5e_cleanup+0x26/0x30 [mlx5_core] cleanup+0xc/0x4e [mlx5_core] __x64_sys_delete_module+0x2b5/0x450 do_syscall_64+0x3d/0x90 entry_SYSCALL_64_after_hwframe+0x46/0xb0
Fixes: e355477ed9e4 ("net/mlx5: Make mlx5_cmd_exec_cb() a safe API") Signed-off-by: Tariq Toukan tariqt@nvidia.com Reviewed-by: Moshe Shemesh moshe@nvidia.com Signed-off-by: Saeed Mahameed saeedm@nvidia.com Link: https://lore.kernel.org/r/20221026135153.154807-8-saeed@kernel.org Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/mellanox/mlx5/core/cmd.c | 10 +++++----- include/linux/mlx5/driver.h | 2 +- 2 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/cmd.c b/drivers/net/ethernet/mellanox/mlx5/core/cmd.c index 6c7b364d0bf0..4fdc97304f69 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/cmd.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/cmd.c @@ -1850,7 +1850,7 @@ void mlx5_cmd_init_async_ctx(struct mlx5_core_dev *dev, ctx->dev = dev; /* Starts at 1 to avoid doing wake_up if we are not cleaning up */ atomic_set(&ctx->num_inflight, 1); - init_waitqueue_head(&ctx->wait); + init_completion(&ctx->inflight_done); } EXPORT_SYMBOL(mlx5_cmd_init_async_ctx);
@@ -1864,8 +1864,8 @@ EXPORT_SYMBOL(mlx5_cmd_init_async_ctx); */ void mlx5_cmd_cleanup_async_ctx(struct mlx5_async_ctx *ctx) { - atomic_dec(&ctx->num_inflight); - wait_event(ctx->wait, atomic_read(&ctx->num_inflight) == 0); + if (!atomic_dec_and_test(&ctx->num_inflight)) + wait_for_completion(&ctx->inflight_done); } EXPORT_SYMBOL(mlx5_cmd_cleanup_async_ctx);
@@ -1876,7 +1876,7 @@ static void mlx5_cmd_exec_cb_handler(int status, void *_work)
work->user_callback(status, work); if (atomic_dec_and_test(&ctx->num_inflight)) - wake_up(&ctx->wait); + complete(&ctx->inflight_done); }
int mlx5_cmd_exec_cb(struct mlx5_async_ctx *ctx, void *in, int in_size, @@ -1892,7 +1892,7 @@ int mlx5_cmd_exec_cb(struct mlx5_async_ctx *ctx, void *in, int in_size, ret = cmd_exec(ctx->dev, in, in_size, out, out_size, mlx5_cmd_exec_cb_handler, work, false); if (ret && atomic_dec_and_test(&ctx->num_inflight)) - wake_up(&ctx->wait); + complete(&ctx->inflight_done);
return ret; } diff --git a/include/linux/mlx5/driver.h b/include/linux/mlx5/driver.h index 2b65ffb3bd76..3a19b9202a12 100644 --- a/include/linux/mlx5/driver.h +++ b/include/linux/mlx5/driver.h @@ -904,7 +904,7 @@ void mlx5_cmd_allowed_opcode(struct mlx5_core_dev *dev, u16 opcode); struct mlx5_async_ctx { struct mlx5_core_dev *dev; atomic_t num_inflight; - struct wait_queue_head wait; + struct completion inflight_done; };
struct mlx5_async_work;