syzkaller on risc-v

[Andreas Schwab]

On Jun 30 2020, Dmitry Vyukov wrote:

> I would assume some stack overflows can happen without KCOV as well.

Yes, I see stack overflows quite a lot, like this:

[62192.908680] Kernel panic - not syncing: corrupted stack end detected inside scheduler
[62192.915752] CPU: 0 PID: 12347 Comm: ld Not tainted 5.7.5-221-default #1 openSUSE Tumbleweed (unreleased)
[62192.925204] Call Trace:
[62192.927646] [<ffffffe0002028ae>] walk_stackframe+0x0/0xaa
[62192.933030] [<ffffffe000202b76>] show_stack+0x2a/0x34
[62192.938066] [<ffffffe000557d44>] dump_stack+0x6e/0x88
[62192.943098] [<ffffffe00020c2d2>] panic+0xe8/0x26a
[62192.947785] [<ffffffe00085ab9c>] schedule+0x0/0xb2
[62192.952561] [<ffffffe00085af36>] _cond_resched+0x32/0x44
[62192.957859] [<ffffffe0002f18ea>] invalidate_mapping_pages+0xe0/0x1ce
[62192.964193] [<ffffffe000370aa4>] inode_lru_isolate+0x238/0x298
[62192.970012] [<ffffffe000308098>] __list_lru_walk_one+0x5e/0xf6
[62192.975826] [<ffffffe000308516>] list_lru_walk_one+0x42/0x98
[62192.981470] [<ffffffe0003717e8>] prune_icache_sb+0x32/0x72
[62192.986941] [<ffffffe000358366>] super_cache_scan+0xe4/0x13e
[62192.992586] [<ffffffe0002f1fac>] do_shrink_slab+0x10e/0x17e
[62192.998142] [<ffffffe0002f2126>] shrink_slab_memcg+0x10a/0x1de
[62193.003957] [<ffffffe0002f5314>] shrink_node_memcgs+0x12e/0x1a4
[62193.009861] [<ffffffe0002f5484>] shrink_node+0xfa/0x43c
[62193.015067] [<ffffffe0002f583e>] shrink_zones+0x78/0x18c
[62193.020365] [<ffffffe0002f59f0>] do_try_to_free_pages+0x9e/0x23e
[62193.026352] [<ffffffe0002f65ac>] try_to_free_pages+0xb2/0xf4
[62193.031991] [<ffffffe000322952>] __alloc_pages_slowpath.constprop.0+0x2d0/0x6c2
[62193.039284] [<ffffffe000322e9a>] __alloc_pages_nodemask+0x156/0x1b2
[62193.045535] [<ffffffe00030c730>] do_anonymous_page+0x58/0x41c
[62193.051266] [<ffffffe00030f50e>] handle_pte_fault+0x12e/0x156
[62193.056994] [<ffffffe000310444>] __handle_mm_fault+0xca/0x118
[62193.062725] [<ffffffe000310532>] handle_mm_fault+0xa0/0x152
[62193.068278] [<ffffffe0002055ba>] do_page_fault+0xd6/0x370
[62193.073666] [<ffffffe00020140a>] ret_from_exception+0x0/0xc
[62193.079222] [<ffffffe0004fc16a>] copy_page_to_iter_iovec+0x4c/0x154

or this:

[200460.114397] Kernel panic - not syncing: corrupted stack end detected inside scheduler
[200460.121553] CPU: 0 PID: 32619 Comm: sh Not tainted 5.7.5-221-default #1 openSUSE Tumbleweed (unreleased)
[200460.131090] Call Trace:
[200460.133623] [<ffffffe0002028ae>] walk_stackframe+0x0/0xaa
[200460.139091] [<ffffffe000202b76>] show_stack+0x2a/0x34
[200460.144212] [<ffffffe000557d44>] dump_stack+0x6e/0x88
[200460.149335] [<ffffffe00020c2d2>] panic+0xe8/0x26a
[200460.154109] [<ffffffe00085ab9c>] schedule+0x0/0xb2
[200460.158969] [<ffffffe00085af36>] _cond_resched+0x32/0x44
[200460.164348] [<ffffffe000498572>] aa_sk_perm+0x38/0x138
[200460.169559] [<ffffffe00048d4b4>] apparmor_socket_sendmsg+0x18/0x20
[200460.175817] [<ffffffe0004508e0>] security_socket_sendmsg+0x2a/0x42
[200460.182061] [<ffffffe0006f4c0a>] sock_sendmsg+0x1a/0x40
[200460.195979] [<ffffffdf817210cc>] xprt_sock_sendmsg+0xb2/0x2b6 [sunrpc]
[200460.210450] [<ffffffdf81723bde>] xs_tcp_send_request+0xc6/0x206 [sunrpc]
[200460.224930] [<ffffffdf8171f538>] xprt_request_transmit.constprop.0+0x88/0x218 [sunrpc]
[200460.240731] [<ffffffdf81720610>] xprt_transmit+0x9a/0x182 [sunrpc]
[200460.254858] [<ffffffdf8171a584>] call_transmit+0x68/0xb8 [sunrpc]
[200460.268817] [<ffffffdf81726660>] __rpc_execute+0x84/0x222 [sunrpc]
[200460.282787] [<ffffffdf81726cea>] rpc_execute+0xac/0xb8 [sunrpc]
[200460.296493] [<ffffffdf8171c5ca>] rpc_run_task+0x122/0x178 [sunrpc]
[200460.314422] [<ffffffdf82e1533a>] nfs4_do_call_sync+0x64/0x84 [nfsv4]
[200460.332514] [<ffffffdf82e1541c>] _nfs4_proc_getattr+0xc2/0xd4 [nfsv4]
[200460.350813] [<ffffffdf82e1cafc>] nfs4_proc_getattr+0x48/0x72 [nfsv4]
[200460.363307] [<ffffffdf8292c1f6>] __nfs_revalidate_inode+0x104/0x2c8 [nfs]
[200460.376204] [<ffffffdf82926d18>] nfs_access_get_cached+0x104/0x212 [nfs]
[200460.389112] [<ffffffdf82926f20>] nfs_do_access+0xfa/0x178 [nfs]
[200460.401176] [<ffffffdf82927070>] nfs_permission+0x8e/0x184 [nfs]
[200460.406497] [<ffffffe000361936>] inode_permission.part.0+0x78/0x118
[200460.412838] [<ffffffe0003638ea>] link_path_walk.part.0+0x1bc/0x212
[200460.419086] [<ffffffe000363c7e>] path_lookupat+0x34/0x172
[200460.424559] [<ffffffe0003653de>] filename_lookup+0x5c/0xf4
[200460.430114] [<ffffffe00036551e>] user_path_at_empty+0x3a/0x5e
[200460.435931] [<ffffffe00035b838>] vfs_statx+0x62/0xbc
[200460.440966] [<ffffffe00035b92a>] __do_sys_newfstatat+0x24/0x3a
[200460.446870] [<ffffffe00035bafa>] sys_newfstatat+0x10/0x18
[200460.452339] [<ffffffe0002013fc>] ret_from_syscall+0x0/0x2

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab at suse.de
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