xref: /openbmc/linux/io_uring/fdinfo.c (revision e40573a4)
1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/kernel.h>
3 #include <linux/errno.h>
4 #include <linux/fs.h>
5 #include <linux/file.h>
6 #include <linux/proc_fs.h>
7 #include <linux/seq_file.h>
8 #include <linux/io_uring.h>
9 
10 #include <uapi/linux/io_uring.h>
11 
12 #include "io_uring.h"
13 #include "sqpoll.h"
14 #include "fdinfo.h"
15 #include "cancel.h"
16 #include "rsrc.h"
17 
18 #ifdef CONFIG_PROC_FS
19 static __cold int io_uring_show_cred(struct seq_file *m, unsigned int id,
20 		const struct cred *cred)
21 {
22 	struct user_namespace *uns = seq_user_ns(m);
23 	struct group_info *gi;
24 	kernel_cap_t cap;
25 	unsigned __capi;
26 	int g;
27 
28 	seq_printf(m, "%5d\n", id);
29 	seq_put_decimal_ull(m, "\tUid:\t", from_kuid_munged(uns, cred->uid));
30 	seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->euid));
31 	seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->suid));
32 	seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->fsuid));
33 	seq_put_decimal_ull(m, "\n\tGid:\t", from_kgid_munged(uns, cred->gid));
34 	seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->egid));
35 	seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->sgid));
36 	seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->fsgid));
37 	seq_puts(m, "\n\tGroups:\t");
38 	gi = cred->group_info;
39 	for (g = 0; g < gi->ngroups; g++) {
40 		seq_put_decimal_ull(m, g ? " " : "",
41 					from_kgid_munged(uns, gi->gid[g]));
42 	}
43 	seq_puts(m, "\n\tCapEff:\t");
44 	cap = cred->cap_effective;
45 	CAP_FOR_EACH_U32(__capi)
46 		seq_put_hex_ll(m, NULL, cap.cap[CAP_LAST_U32 - __capi], 8);
47 	seq_putc(m, '\n');
48 	return 0;
49 }
50 
51 static __cold void __io_uring_show_fdinfo(struct io_ring_ctx *ctx,
52 					  struct seq_file *m)
53 {
54 	struct io_sq_data *sq = NULL;
55 	struct io_overflow_cqe *ocqe;
56 	struct io_rings *r = ctx->rings;
57 	unsigned int sq_mask = ctx->sq_entries - 1, cq_mask = ctx->cq_entries - 1;
58 	unsigned int sq_head = READ_ONCE(r->sq.head);
59 	unsigned int sq_tail = READ_ONCE(r->sq.tail);
60 	unsigned int cq_head = READ_ONCE(r->cq.head);
61 	unsigned int cq_tail = READ_ONCE(r->cq.tail);
62 	unsigned int cq_shift = 0;
63 	unsigned int sq_entries, cq_entries;
64 	bool has_lock;
65 	bool is_cqe32 = (ctx->flags & IORING_SETUP_CQE32);
66 	unsigned int i;
67 
68 	if (is_cqe32)
69 		cq_shift = 1;
70 
71 	/*
72 	 * we may get imprecise sqe and cqe info if uring is actively running
73 	 * since we get cached_sq_head and cached_cq_tail without uring_lock
74 	 * and sq_tail and cq_head are changed by userspace. But it's ok since
75 	 * we usually use these info when it is stuck.
76 	 */
77 	seq_printf(m, "SqMask:\t0x%x\n", sq_mask);
78 	seq_printf(m, "SqHead:\t%u\n", sq_head);
79 	seq_printf(m, "SqTail:\t%u\n", sq_tail);
80 	seq_printf(m, "CachedSqHead:\t%u\n", ctx->cached_sq_head);
81 	seq_printf(m, "CqMask:\t0x%x\n", cq_mask);
82 	seq_printf(m, "CqHead:\t%u\n", cq_head);
83 	seq_printf(m, "CqTail:\t%u\n", cq_tail);
84 	seq_printf(m, "CachedCqTail:\t%u\n", ctx->cached_cq_tail);
85 	seq_printf(m, "SQEs:\t%u\n", sq_tail - ctx->cached_sq_head);
86 	sq_entries = min(sq_tail - sq_head, ctx->sq_entries);
87 	for (i = 0; i < sq_entries; i++) {
88 		unsigned int entry = i + sq_head;
89 		unsigned int sq_idx = READ_ONCE(ctx->sq_array[entry & sq_mask]);
90 		struct io_uring_sqe *sqe;
91 
92 		if (sq_idx > sq_mask)
93 			continue;
94 		sqe = &ctx->sq_sqes[sq_idx];
95 		seq_printf(m, "%5u: opcode:%d, fd:%d, flags:%x, user_data:%llu\n",
96 			   sq_idx, sqe->opcode, sqe->fd, sqe->flags,
97 			   sqe->user_data);
98 	}
99 	seq_printf(m, "CQEs:\t%u\n", cq_tail - cq_head);
100 	cq_entries = min(cq_tail - cq_head, ctx->cq_entries);
101 	for (i = 0; i < cq_entries; i++) {
102 		unsigned int entry = i + cq_head;
103 		struct io_uring_cqe *cqe = &r->cqes[(entry & cq_mask) << cq_shift];
104 
105 		if (!is_cqe32) {
106 			seq_printf(m, "%5u: user_data:%llu, res:%d, flag:%x\n",
107 			   entry & cq_mask, cqe->user_data, cqe->res,
108 			   cqe->flags);
109 		} else {
110 			seq_printf(m, "%5u: user_data:%llu, res:%d, flag:%x, "
111 				"extra1:%llu, extra2:%llu\n",
112 				entry & cq_mask, cqe->user_data, cqe->res,
113 				cqe->flags, cqe->big_cqe[0], cqe->big_cqe[1]);
114 		}
115 	}
116 
117 	/*
118 	 * Avoid ABBA deadlock between the seq lock and the io_uring mutex,
119 	 * since fdinfo case grabs it in the opposite direction of normal use
120 	 * cases. If we fail to get the lock, we just don't iterate any
121 	 * structures that could be going away outside the io_uring mutex.
122 	 */
123 	has_lock = mutex_trylock(&ctx->uring_lock);
124 
125 	if (has_lock && (ctx->flags & IORING_SETUP_SQPOLL)) {
126 		sq = ctx->sq_data;
127 		if (!sq->thread)
128 			sq = NULL;
129 	}
130 
131 	seq_printf(m, "SqThread:\t%d\n", sq ? task_pid_nr(sq->thread) : -1);
132 	seq_printf(m, "SqThreadCpu:\t%d\n", sq ? task_cpu(sq->thread) : -1);
133 	seq_printf(m, "UserFiles:\t%u\n", ctx->nr_user_files);
134 	for (i = 0; has_lock && i < ctx->nr_user_files; i++) {
135 		struct file *f = io_file_from_index(&ctx->file_table, i);
136 
137 		if (f)
138 			seq_printf(m, "%5u: %s\n", i, file_dentry(f)->d_iname);
139 		else
140 			seq_printf(m, "%5u: <none>\n", i);
141 	}
142 	seq_printf(m, "UserBufs:\t%u\n", ctx->nr_user_bufs);
143 	for (i = 0; has_lock && i < ctx->nr_user_bufs; i++) {
144 		struct io_mapped_ubuf *buf = ctx->user_bufs[i];
145 		unsigned int len = buf->ubuf_end - buf->ubuf;
146 
147 		seq_printf(m, "%5u: 0x%llx/%u\n", i, buf->ubuf, len);
148 	}
149 	if (has_lock && !xa_empty(&ctx->personalities)) {
150 		unsigned long index;
151 		const struct cred *cred;
152 
153 		seq_printf(m, "Personalities:\n");
154 		xa_for_each(&ctx->personalities, index, cred)
155 			io_uring_show_cred(m, index, cred);
156 	}
157 	if (has_lock)
158 		mutex_unlock(&ctx->uring_lock);
159 
160 	seq_puts(m, "PollList:\n");
161 	for (i = 0; i < (1U << ctx->cancel_table.hash_bits); i++) {
162 		struct io_hash_bucket *hb = &ctx->cancel_table.hbs[i];
163 		struct io_kiocb *req;
164 
165 		spin_lock(&hb->lock);
166 		hlist_for_each_entry(req, &hb->list, hash_node)
167 			seq_printf(m, "  op=%d, task_works=%d\n", req->opcode,
168 					task_work_pending(req->task));
169 		spin_unlock(&hb->lock);
170 	}
171 
172 	seq_puts(m, "CqOverflowList:\n");
173 	spin_lock(&ctx->completion_lock);
174 	list_for_each_entry(ocqe, &ctx->cq_overflow_list, list) {
175 		struct io_uring_cqe *cqe = &ocqe->cqe;
176 
177 		seq_printf(m, "  user_data=%llu, res=%d, flags=%x\n",
178 			   cqe->user_data, cqe->res, cqe->flags);
179 
180 	}
181 
182 	spin_unlock(&ctx->completion_lock);
183 }
184 
185 __cold void io_uring_show_fdinfo(struct seq_file *m, struct file *f)
186 {
187 	struct io_ring_ctx *ctx = f->private_data;
188 
189 	if (percpu_ref_tryget(&ctx->refs)) {
190 		__io_uring_show_fdinfo(ctx, m);
191 		percpu_ref_put(&ctx->refs);
192 	}
193 }
194 #endif
195