This is a note to let you know that I've just added the patch titled net/tls: race causes kernel panic to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net-tls-race-causes-kernel-panic.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 38f7e1c0c43dd25b06513137bb6fd35476f9ec6d Mon Sep 17 00:00:00 2001 From: Rohit Maheshwari <rohitm@xxxxxxxxxxx> Date: Thu, 24 Sep 2020 12:28:45 +0530 Subject: net/tls: race causes kernel panic From: Rohit Maheshwari <rohitm@xxxxxxxxxxx> commit 38f7e1c0c43dd25b06513137bb6fd35476f9ec6d upstream. BUG: kernel NULL pointer dereference, address: 00000000000000b8 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 80000008b6fef067 P4D 80000008b6fef067 PUD 8b6fe6067 PMD 0 Oops: 0000 [#1] SMP PTI CPU: 12 PID: 23871 Comm: kworker/12:80 Kdump: loaded Tainted: G S 5.9.0-rc3+ #1 Hardware name: Supermicro X10SRA-F/X10SRA-F, BIOS 2.1 03/29/2018 Workqueue: events tx_work_handler [tls] RIP: 0010:tx_work_handler+0x1b/0x70 [tls] Code: dc fe ff ff e8 16 d4 a3 f6 66 0f 1f 44 00 00 0f 1f 44 00 00 55 53 48 8b 6f 58 48 8b bd a0 04 00 00 48 85 ff 74 1c 48 8b 47 28 <48> 8b 90 b8 00 00 00 83 e2 02 75 0c f0 48 0f ba b0 b8 00 00 00 00 RSP: 0018:ffffa44ace61fe88 EFLAGS: 00010286 RAX: 0000000000000000 RBX: ffff91da9e45cc30 RCX: dead000000000122 RDX: 0000000000000001 RSI: ffff91da9e45cc38 RDI: ffff91d95efac200 RBP: ffff91da133fd780 R08: 0000000000000000 R09: 000073746e657665 R10: 8080808080808080 R11: 0000000000000000 R12: ffff91dad7d30700 R13: ffff91dab6561080 R14: 0ffff91dad7d3070 R15: ffff91da9e45cc38 FS: 0000000000000000(0000) GS:ffff91dad7d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000000000b8 CR3: 0000000906478003 CR4: 00000000003706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: process_one_work+0x1a7/0x370 worker_thread+0x30/0x370 ? process_one_work+0x370/0x370 kthread+0x114/0x130 ? kthread_park+0x80/0x80 ret_from_fork+0x22/0x30 tls_sw_release_resources_tx() waits for encrypt_pending, which can have race, so we need similar changes as in commit 0cada33241d9de205522e3858b18e506ca5cce2c here as well. Fixes: a42055e8d2c3 ("net/tls: Add support for async encryption of records for performance") Signed-off-by: Rohit Maheshwari <rohitm@xxxxxxxxxxx> Acked-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/tls/tls_sw.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) --- a/net/tls/tls_sw.c +++ b/net/tls/tls_sw.c @@ -2137,10 +2137,15 @@ void tls_sw_release_resources_tx(struct struct tls_context *tls_ctx = tls_get_ctx(sk); struct tls_sw_context_tx *ctx = tls_sw_ctx_tx(tls_ctx); struct tls_rec *rec, *tmp; + int pending; /* Wait for any pending async encryptions to complete */ - smp_store_mb(ctx->async_notify, true); - if (atomic_read(&ctx->encrypt_pending)) + spin_lock_bh(&ctx->encrypt_compl_lock); + ctx->async_notify = true; + pending = atomic_read(&ctx->encrypt_pending); + spin_unlock_bh(&ctx->encrypt_compl_lock); + + if (pending) crypto_wait_req(-EINPROGRESS, &ctx->async_wait); tls_tx_records(sk, -1); Patches currently in stable-queue which might be from rohitm@xxxxxxxxxxx are queue-5.4/net-tls-race-causes-kernel-panic.patch