Hello, I am getting the following reports with low frequency while running syzkaller fuzzer. Unfortunately they are not reproducible and happen in a background thread, so it is difficult to extract any context on my side. I see only few such crashes per week, so most likely it is some hard to trigger data race. The following reports are from mmotm tree, commits 00e20cfc2bf04a0cbe1f5405f61c8426f43eee84 and fff7e71eac7788904753136f09bcad7471f7799e. Any ideas as to how this can happen? BUG: unable to handle kernel NULL pointer dereference at 0000000000000060 IP: [<ffffffff813fc09e>] sha512_mb_mgr_get_comp_job_avx2+0x6e/0xee arch/x86/crypto/sha512-mb/sha512_mb_mgr_flush_avx2.S:251 PGD 1d2395067 [ 220.874864] PUD 1d2860067 Oops: 0002 [#1] SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 0 PID: 516 Comm: kworker/0:1 Not tainted 4.9.0 #4 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: crypto mcryptd_queue_worker task: ffff8801d9f346c0 task.stack: ffff8801d9f08000 RIP: 0010:[<ffffffff813fc09e>] [<ffffffff813fc09e>] sha512_mb_mgr_get_comp_job_avx2+0x6e/0xee arch/x86/crypto/sha512-mb/sha512_mb_mgr_flush_avx2.S:251 RSP: 0018:ffff8801d9f0eef8 EFLAGS: 00010202 RAX: 0000000000000000 RBX: ffff8801d7db1190 RCX: 0000000000000006 RDX: 0000000000000001 RSI: ffff8801d9f34ee8 RDI: ffff8801d7db1040 RBP: ffff8801d9f0f258 R08: 0000000100000000 R09: 0000000000000001 R10: 0000000000000002 R11: 0000000000000003 R12: ffff8801d9f0f230 R13: ffff8801c8bbc4e0 R14: ffff8801c8bbc530 R15: ffff8801d9f0ef70 FS: 0000000000000000(0000) GS:ffff8801dc000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000060 CR3: 00000001cc15a000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffff8801d7db1040 ffffffff813fa207 dffffc0000000000 ffffe8ffffc0f238 0000000000000002 1ffff1003b3e1dea ffffe8ffffc0f218 ffff8801d9f0f190 0000000000000282 ffffe8ffffc0f140 ffffe8ffffc0f220 0000000041b58ab3 Call Trace: [<ffffffff813fb407>] sha512_mb_update+0x2f7/0x4e0 arch/x86/crypto/sha512-mb/sha512_mb.c:588 [<ffffffff8219d4ad>] crypto_ahash_update include/crypto/hash.h:512 [inline] [<ffffffff8219d4ad>] ahash_mcryptd_update crypto/mcryptd.c:627 [inline] [<ffffffff8219d4ad>] mcryptd_hash_update+0xcd/0x1c0 crypto/mcryptd.c:373 [<ffffffff8219c99f>] mcryptd_queue_worker+0xff/0x6a0 crypto/mcryptd.c:181 [<ffffffff81492960>] process_one_work+0xbd0/0x1c10 kernel/workqueue.c:2096 [<ffffffff81493bc3>] worker_thread+0x223/0x1990 kernel/workqueue.c:2230 [<ffffffff814abb33>] kthread+0x323/0x3e0 kernel/kthread.c:209 [<ffffffff8436fbaa>] ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:433 Code: 49 0f 42 d3 48 f7 c2 f0 ff ff ff 0f 85 9a 00 00 00 48 83 e2 0f 48 6b da 08 48 8d 9c 1f 48 01 00 00 48 8b 03 48 c7 03 00 00 00 00 <c7> 40 60 02 00 00 00 48 8b 9f 40 01 00 00 48 c1 e3 08 48 09 d3 RIP [<ffffffff813fc09e>] sha512_mb_mgr_get_comp_job_avx2+0x6e/0xee arch/x86/crypto/sha512-mb/sha512_mb_mgr_flush_avx2.S:251 RSP <ffff8801d9f0eef8> CR2: 0000000000000060 ---[ end trace 139fd4cda5dfe2c4 ]--- BUG: unable to handle kernel NULL pointer dereference at 0000000000000060 IP: [<ffffffff813fc09e>] sha512_mb_mgr_get_comp_job_avx2+0x6e/0xee arch/x86/crypto/sha512-mb/sha512_mb_mgr_flush_avx2.S:251 PGD 1c68ad067 [ 624.973638] PUD 1d485a067 Oops: 0002 [#1] SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 0 PID: 517 Comm: kworker/0:1 Not tainted 4.9.0 #3 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: crypto mcryptd_queue_worker task: ffff8801d9e64700 task.stack: ffff8801d9838000 RIP: 0010:[<ffffffff813fc09e>] [<ffffffff813fc09e>] sha512_mb_mgr_get_comp_job_avx2+0x6e/0xee arch/x86/crypto/sha512-mb/sha512_mb_mgr_flush_avx2.S:251 RSP: 0018:ffff8801d983eef8 EFLAGS: 00010202 RAX: 0000000000000000 RBX: ffff8801d7d96950 RCX: 0000000000000006 RDX: 0000000000000001 RSI: ffff8801d9e64f28 RDI: ffff8801d7d96800 RBP: ffff8801d983f258 R08: 0000000100000000 R09: 0000000000000001 R10: 0000000000000002 R11: 0000000000000003 R12: ffff8801d983f230 R13: ffff8801b67f5720 R14: ffff8801b67f5770 R15: ffff8801d983ef70 FS: 0000000000000000(0000) GS:ffff8801dc000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000060 CR3: 00000001cee58000 CR4: 00000000001406f0 Stack: ffff8801d7d96800 ffffffff813fa207 dffffc0000000000 ffffe8ffffc0f238 0000000000000002 1ffff1003b307dea ffffe8ffffc0f218 ffff8801d983f190 0000000000000282 ffffe8ffffc0f140 ffffe8ffffc0f220 0000000041b58ab3 Call Trace: [<ffffffff813fb407>] sha512_mb_update+0x2f7/0x4e0 arch/x86/crypto/sha512-mb/sha512_mb.c:588 [<ffffffff8219cdad>] crypto_ahash_update include/crypto/hash.h:512 [inline] [<ffffffff8219cdad>] ahash_mcryptd_update crypto/mcryptd.c:627 [inline] [<ffffffff8219cdad>] mcryptd_hash_update+0xcd/0x1c0 crypto/mcryptd.c:373 [<ffffffff8219c29f>] mcryptd_queue_worker+0xff/0x6a0 crypto/mcryptd.c:181 [<ffffffff81492960>] process_one_work+0xbd0/0x1c10 kernel/workqueue.c:2096 [<ffffffff81493bc3>] worker_thread+0x223/0x1990 kernel/workqueue.c:2230 [<ffffffff814abb33>] kthread+0x323/0x3e0 kernel/kthread.c:209 [<ffffffff8436fbea>] ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:433 Code: 49 0f 42 d3 48 f7 c2 f0 ff ff ff 0f 85 9a 00 00 00 48 83 e2 0f 48 6b da 08 48 8d 9c 1f 48 01 00 00 48 8b 03 48 c7 03 00 00 00 00 <c7> 40 60 02 00 00 00 48 8b 9f 40 01 00 00 48 c1 e3 08 48 09 d3 RIP [<ffffffff813fc09e>] sha512_mb_mgr_get_comp_job_avx2+0x6e/0xee arch/x86/crypto/sha512-mb/sha512_mb_mgr_flush_avx2.S:251 RSP <ffff8801d983eef8> CR2: 0000000000000060 ---[ end trace 76403e033556dcb7 ]--- BUG: unable to handle kernel NULL pointer dereference at 0000000000000060 IP: [<ffffffff813fc09e>] sha512_mb_mgr_get_comp_job_avx2+0x6e/0xee arch/x86/crypto/sha512-mb/sha512_mb_mgr_flush_avx2.S:251 PGD 1d6242067 [ 226.248182] PUD 1d2093067 Oops: 0002 [#1] SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 1 PID: 1788 Comm: kworker/1:2 Not tainted 4.9.0 #3 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: crypto mcryptd_queue_worker task: ffff8801cc3ee100 task.stack: ffff8801cd068000 RIP: 0010:[<ffffffff813fc09e>] [<ffffffff813fc09e>] sha512_mb_mgr_get_comp_job_avx2+0x6e/0xee arch/x86/crypto/sha512-mb/sha512_mb_mgr_flush_avx2.S:251 RSP: 0018:ffff8801cd06eef8 EFLAGS: 00010202 RAX: 0000000000000000 RBX: ffff8801d7dc3c10 RCX: 0000000000000006 RDX: 0000000000000001 RSI: ffff8801cc3ee928 RDI: ffff8801d7dc3ac0 RBP: ffff8801cd06f258 R08: 0000000100000000 R09: 0000000000000001 R10: 0000000000000002 R11: 0000000000000003 R12: ffff8801cd06f230 R13: ffff8801c6eb9aa0 R14: ffff8801c6eb9af0 R15: ffff8801cd06ef70 FS: 0000000000000000(0000) GS:ffff8801dc100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000060 CR3: 00000001d6201000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffff8801d7dc3ac0 ffffffff813fa207 dffffc0000000000 ffffe8ffffd0f238 0000000000000002 1ffff10039a0ddea ffffe8ffffd0f218 ffff8801cd06f190 0000000000000282 ffffe8ffffd0f140 ffffe8ffffd0f220 0000000041b58ab3 Call Trace: [<ffffffff813fb407>] sha512_mb_update+0x2f7/0x4e0 arch/x86/crypto/sha512-mb/sha512_mb.c:588 [<ffffffff8219cdad>] crypto_ahash_update include/crypto/hash.h:512 [inline] [<ffffffff8219cdad>] ahash_mcryptd_update crypto/mcryptd.c:627 [inline] [<ffffffff8219cdad>] mcryptd_hash_update+0xcd/0x1c0 crypto/mcryptd.c:373 [<ffffffff8219c29f>] mcryptd_queue_worker+0xff/0x6a0 crypto/mcryptd.c:181 [<ffffffff81492960>] process_one_work+0xbd0/0x1c10 kernel/workqueue.c:2096 [<ffffffff81493bc3>] worker_thread+0x223/0x1990 kernel/workqueue.c:2230 [<ffffffff814abb33>] kthread+0x323/0x3e0 kernel/kthread.c:209 [<ffffffff8436fbea>] ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:433 Code: 49 0f 42 d3 48 f7 c2 f0 ff ff ff 0f 85 9a 00 00 00 48 83 e2 0f 48 6b da 08 48 8d 9c 1f 48 01 00 00 48 8b 03 48 c7 03 00 00 00 00 <c7> 40 60 02 00 00 00 48 8b 9f 40 01 00 00 48 c1 e3 08 48 09 d3 RIP [<ffffffff813fc09e>] sha512_mb_mgr_get_comp_job_avx2+0x6e/0xee arch/x86/crypto/sha512-mb/sha512_mb_mgr_flush_avx2.S:251 RSP <ffff8801cd06eef8> CR2: 0000000000000060 ---[ end trace 47d3302a6c62cfbc ]--- BUG: unable to handle kernel NULL pointer dereference at 0000000000000060 IP: [<ffffffff813fc09e>] sha512_mb_mgr_get_comp_job_avx2+0x6e/0xee arch/x86/crypto/sha512-mb/sha512_mb_mgr_flush_avx2.S:251 PGD 1ccad4067 [ 32.785777] PUD 1cb96c067 Oops: 0002 [#1] SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 1 PID: 3231 Comm: kworker/1:2 Not tainted 4.9.0 #3 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: crypto mcryptd_queue_worker task: ffff8801cf472700 task.stack: ffff8801ce848000 RIP: 0010:[<ffffffff813fc09e>] [<ffffffff813fc09e>] sha512_mb_mgr_get_comp_job_avx2+0x6e/0xee arch/x86/crypto/sha512-mb/sha512_mb_mgr_flush_avx2.S:251 RSP: 0018:ffff8801ce84eef8 EFLAGS: 00010202 RAX: 0000000000000000 RBX: ffff8801d7c82950 RCX: 0000000000000006 RDX: 0000000000000001 RSI: ffff8801cf472f28 RDI: ffff8801d7c82800 RBP: ffff8801ce84f258 R08: 0000000100000000 R09: 0000000000000001 R10: 0000000000000002 R11: 0000000000000003 R12: ffff8801ce84f230 R13: ffff8801c970e760 R14: ffff8801c970e7b0 R15: ffff8801ce84ef70 FS: 0000000000000000(0000) GS:ffff8801dc100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000060 CR3: 00000001ca654000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffff8801d7c82800 ffffffff813fa207 dffffc0000000000 ffffe8ffffd0f238 0000000000000002 1ffff10039d09dea ffffe8ffffd0f218 ffff8801ce84f190 0000000000000282 ffffe8ffffd0f140 ffffe8ffffd0f220 0000000041b58ab3 Call Trace: [<ffffffff813fb407>] sha512_mb_update+0x2f7/0x4e0 arch/x86/crypto/sha512-mb/sha512_mb.c:588 [<ffffffff8219cdad>] crypto_ahash_update include/crypto/hash.h:512 [inline] [<ffffffff8219cdad>] ahash_mcryptd_update crypto/mcryptd.c:627 [inline] [<ffffffff8219cdad>] mcryptd_hash_update+0xcd/0x1c0 crypto/mcryptd.c:373 [<ffffffff8219c29f>] mcryptd_queue_worker+0xff/0x6a0 crypto/mcryptd.c:181 [<ffffffff81492960>] process_one_work+0xbd0/0x1c10 kernel/workqueue.c:2096 [<ffffffff81493bc3>] worker_thread+0x223/0x1990 kernel/workqueue.c:2230 [<ffffffff814abb33>] kthread+0x323/0x3e0 kernel/kthread.c:209 [<ffffffff8436fbea>] ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:433 Code: 49 0f 42 d3 48 f7 c2 f0 ff ff ff 0f 85 9a 00 00 00 48 83 e2 0f 48 6b da 08 48 8d 9c 1f 48 01 00 00 48 8b 03 48 c7 03 00 00 00 00 <c7> 40 60 02 00 00 00 48 8b 9f 40 01 00 00 48 c1 e3 08 48 09 d3 RIP [<ffffffff813fc09e>] sha512_mb_mgr_get_comp_job_avx2+0x6e/0xee arch/x86/crypto/sha512-mb/sha512_mb_mgr_flush_avx2.S:251 RSP <ffff8801ce84eef8> CR2: 0000000000000060 ---[ end trace 3af8184eabd21203 ]--- -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
