Commits · 4ee3631451c9a62e6b6bc7ee51fb9a5b34e33509 · Mirrors / github.com / raspberrypi_linux

May 01, 2020

io_uring: check non-sync defer_list carefully · 4ee36314

Pavel Begunkov authored May 01, 2020



io_req_defer() do double-checked locking. Use proper helpers for that,
i.e. list_empty_careful().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

4ee36314

io_uring: fix extra put in sync_file_range() · 7759a0bf

Pavel Begunkov authored May 01, 2020



[   40.179474] refcount_t: underflow; use-after-free.
[   40.179499] WARNING: CPU: 6 PID: 1848 at lib/refcount.c:28 refcount_warn_saturate+0xae/0xf0
...
[   40.179612] RIP: 0010:refcount_warn_saturate+0xae/0xf0
[   40.179617] Code: 28 44 0a 01 01 e8 d7 01 c2 ff 0f 0b 5d c3 80 3d 15 44 0a 01 00 75 91 48 c7 c7 b8 f5 75 be c6 05 05 44 0a 01 01 e8 b7 01 c2 ff <0f> 0b 5d c3 80 3d f3 43 0a 01 00 0f 85 6d ff ff ff 48 c7 c7 10 f6
[   40.179619] RSP: 0018:ffffb252423ebe18 EFLAGS: 00010286
[   40.179623] RAX: 0000000000000000 RBX: ffff98d65e929400 RCX: 0000000000000000
[   40.179625] RDX: 0000000000000001 RSI: 0000000000000086 RDI: 00000000ffffffff
[   40.179627] RBP: ffffb252423ebe18 R08: 0000000000000001 R09: 000000000000055d
[   40.179629] R10: 0000000000000c8c R11: 0000000000000001 R12: 0000000000000000
[   40.179631] R13: ffff98d68c434400 R14: ffff98d6a9cbaa20 R15: ffff98d6a609ccb8
[   40.179634] FS:  0000000000000000(0000) GS:ffff98d6af580000(0000) knlGS:0000000000000000
[   40.179636] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   40.179638] CR2: 00000000033e3194 CR3: 000000006480a003 CR4: 00000000003606e0
[   40.179641] Call Trace:
[   40.179652]  io_put_req+0x36/0x40
[   40.179657]  io_free_work+0x15/0x20
[   40.179661]  io_worker_handle_work+0x2f5/0x480
[   40.179667]  io_wqe_worker+0x2a9/0x360
[   40.179674]  ? _raw_spin_unlock_irqrestore+0x24/0x40
[   40.179681]  kthread+0x12c/0x170
[   40.179685]  ? io_worker_handle_work+0x480/0x480
[   40.179690]  ? kthread_park+0x90/0x90
[   40.179695]  ret_from_fork+0x35/0x40
[   40.179702] ---[ end trace 85027405f00110aa ]---

Opcode handler must never put submission ref, but that's what
io_sync_file_range_finish() do. use io_steal_work() there.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

7759a0bf

io_uring: use cond_resched() in io_ring_ctx_wait_and_kill() · 3fd44c86

Xiaoguang Wang authored May 01, 2020



While working on to make io_uring sqpoll mode support syscalls that need
struct files_struct, I got cpu soft lockup in io_ring_ctx_wait_and_kill(),

    while (ctx->sqo_thread && !wq_has_sleeper(&ctx->sqo_wait))
        cpu_relax();

above loop never has an chance to exit, it's because preempt isn't enabled
in the kernel, and the context calling io_ring_ctx_wait_and_kill() and
io_sq_thread() run in the same cpu, if io_sq_thread calls a cond_resched()
yield cpu and another context enters above loop, then io_sq_thread() will
always in runqueue and never exit.

Use cond_resched() can fix this issue.

Reported-by:  <syzbot+66243bb7126c410cefe6@syzkaller.appspotmail.com>
Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

3fd44c86

io_uring: use proper references for fallback_req locking · dd461af6

Bijan Mottahedeh authored Apr 29, 2020



Use ctx->fallback_req address for test_and_set_bit_lock() and
clear_bit_unlock().

Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

dd461af6

io_uring: only force async punt if poll based retry can't handle it · 490e8967

Jens Axboe authored Apr 28, 2020



We do blocking retry from our poll handler, if the file supports polled
notifications. Only mark the request as needing an async worker if we
can't poll for it.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

490e8967

io_uring: enable poll retry for any file with ->read_iter / ->write_iter · af197f50

Jens Axboe authored Apr 28, 2020



We can have files like eventfd where it's perfectly fine to do poll
based retry on them, right now io_file_supports_async() doesn't take
that into account.

Pass in data direction and check the f_op instead of just always needing
an async worker.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

af197f50

Apr 28, 2020

io_uring: statx must grab the file table for valid fd · 5b0bbee4

Jens Axboe authored Apr 27, 2020



Clay reports that OP_STATX fails for a test case with a valid fd
and empty path:

 -- Test 0: statx:fd 3: SUCCEED, file mode 100755
 -- Test 1: statx:path ./uring_statx: SUCCEED, file mode 100755
 -- Test 2: io_uring_statx:fd 3: FAIL, errno 9: Bad file descriptor
 -- Test 3: io_uring_statx:path ./uring_statx: SUCCEED, file mode 100755

This is due to statx not grabbing the process file table, hence we can't
lookup the fd in async context. If the fd is valid, ensure that we grab
the file table so we can grab the file from async context.

Cc: stable@vger.kernel.org # v5.6
Reported-by: Clay Harris <bugs@claycon.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

5b0bbee4

Apr 20, 2020

io_uring: only restore req->work for req that needs do completion · 44575a67

Xiaoguang Wang authored Apr 19, 2020

When testing io_uring IORING_FEAT_FAST_POLL feature, I got below panic:
BUG: kernel NULL pointer dereference, address: 0000000000000030
PGD 0 P4D 0
Oops: 0000 [#1] SMP PTI
CPU: 5 PID: 2154 Comm: io_uring_echo_s Not tainted 5.6.0+ #359
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS rel-1.11.1-0-g0551a4be2c-prebuilt.qemu-project.org 04/01/2014
RIP: 0010:io_wq_submit_work+0xf/0xa0
Code: ff ff ff be 02 00 00 00 e8 ae c9 19 00 e9 58 ff ff ff 66 0f 1f
84 00 00 00 00 00 0f 1f 44 00 00 41 54 49 89 fc 55 53 48 8b 2f <8b>
45 30 48 8d 9d 48 ff ff ff 25 01 01 00 00 83 f8 01 75 07 eb 2a
RSP: 0018:ffffbef543e93d58 EFLAGS: 00010286
RAX: ffffffff84364f50 RBX: ffffa3eb50f046b8 RCX: 0000000000000000
RDX: ffffa3eb0efc1840 RSI: 0000000000000006 RDI: ffffa3eb50f046b8
RBP: 0000000000000000 R08: 00000000fffd070d R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffa3eb50f046b8
R13: ffffa3eb0efc2088 R14: ffffffff85b69be0 R15: ffffa3eb0effa4b8
FS:  00007fe9f69cc4c0(0000) GS:ffffa3eb5ef40000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000030 CR3: 0000000020410000 CR4: 00000000000006e0
Call Trace:
 task_work_run+0x6d/0xa0
 do_exit+0x39a/0xb80
 ? get_signal+0xfe/0xbc0
 do_group_exit+0x47/0xb0
 get_signal+0x14b/0xbc0
 ? __x64_sys_io_uring_enter+0x1b7/0x450
 do_signal+0x2c/0x260
 ? __x64_sys_io_uring_enter+0x228/0x450
 exit_to_usermode_loop+0x87/0xf0
 do_syscall_64+0x209/0x230
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x7fe9f64f8df9
Code: Bad RIP value.

task_work_run calls io_wq_submit_work unexpectedly, it's obvious that
struct callback_head's func member has been changed. After looking into
codes, I found this issue is still due to the union definition:
    union {
        /*
         * Only commands that never go async can use the below fields,
         * obviously. Right now only IORING_OP_POLL_ADD uses them, and
         * async armed poll handlers for regular commands. The latter
         * restore the work, if needed.
         */
        struct {
            struct callback_head	task_work;
            struct hlist_node	hash_node;
            struct async_poll	*apoll;
        };
        struct io_wq_work	work;
    };

When task_work_run has multiple work to execute, the work that calls
io_poll_remove_all() will do req->work restore for  non-poll request
always, but indeed if a non-poll request has been added to a new
callback_head, subsequent callback will call io_async_task_func() to
handle this request, that means we should not do the restore work
for such non-poll request. Meanwhile in io_async_task_func(), we should
drop submit ref when req has been canceled.

Fix both issues.

Fixes: b1f573bd

 ("io_uring: restore req->work when canceling poll request")
Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

Use io_double_put_req()

Signed-off-by: Jens Axboe <axboe@kernel.dk>

44575a67

Apr 15, 2020

io_uring: don't count rqs failed after current one · 31af27c7

Pavel Begunkov authored Apr 15, 2020



When checking for draining with __req_need_defer(), it tries to match
how many requests were sent before a current one with number of already
completed. Dropped SQEs are included in req->sequence, and they won't
ever appear in CQ. To compensate for that, __req_need_defer() substracts
ctx->cached_sq_dropped.
However, what it should really use is number of SQEs dropped __before__
the current one. In other words, any submitted request shouldn't
shouldn't affect dequeueing from the drain queue of previously submitted
ones.

Instead of saving proper ctx->cached_sq_dropped in each request,
substract from req->sequence it at initialisation, so it includes number
of properly submitted requests.

note: it also changes behaviour of timeouts, but
1. it's already diverge from the description because of using SQ
2. the description is ambiguous regarding dropped SQEs

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

31af27c7

io_uring: kill already cached timeout.seq_offset · b55ce732

Pavel Begunkov authored Apr 15, 2020



req->timeout.count and req->io->timeout.seq_offset store the same value,
which is sqe->off. Kill the second one

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

b55ce732

io_uring: fix cached_sq_head in io_timeout() · 22cad158

Pavel Begunkov authored Apr 15, 2020



io_timeout() can be executed asynchronously by a worker and without
holding ctx->uring_lock

1. using ctx->cached_sq_head there is racy there
2. it should count events from a moment of timeout's submission, but
not execution

Use req->sequence.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

22cad158

Apr 14, 2020

io_uring: only post events in io_poll_remove_all() if we completed some · 8e2e1faf

Jens Axboe authored Apr 13, 2020



syzbot reports this crash:

BUG: unable to handle page fault for address: ffffffffffffffe8
PGD f96e17067 P4D f96e17067 PUD f96e19067 PMD 0
Oops: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI
CPU: 55 PID: 211750 Comm: trinity-c127 Tainted: G    B        L    5.7.0-rc1-next-20200413 #4
Hardware name: HP ProLiant DL380 Gen9/ProLiant DL380 Gen9, BIOS P89 04/12/2017
RIP: 0010:__wake_up_common+0x98/0x290
el/sched/wait.c:87
Code: 40 4d 8d 78 e8 49 8d 7f 18 49 39 fd 0f 84 80 00 00 00 e8 6b bd 2b 00 49 8b 5f 18 45 31 e4 48 83 eb 18 4c 89 ff e8 08 bc 2b 00 <45> 8b 37 41 f6 c6 04 75 71 49 8d 7f 10 e8 46 bd 2b 00 49 8b 47 10
RSP: 0018:ffffc9000adbfaf0 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffffffffffffffe8 RCX: ffffffffaa9636b8
RDX: 0000000000000003 RSI: dffffc0000000000 RDI: ffffffffffffffe8
RBP: ffffc9000adbfb40 R08: fffffbfff582c5fd R09: fffffbfff582c5fd
R10: ffffffffac162fe3 R11: fffffbfff582c5fc R12: 0000000000000000
R13: ffff888ef82b0960 R14: ffffc9000adbfb80 R15: ffffffffffffffe8
FS:  00007fdcba4c4740(0000) GS:ffff889033780000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffe8 CR3: 0000000f776a0004 CR4: 00000000001606e0
Call Trace:
 __wake_up_common_lock+0xea/0x150
ommon_lock at kernel/sched/wait.c:124
 ? __wake_up_common+0x290/0x290
 ? lockdep_hardirqs_on+0x16/0x2c0
 __wake_up+0x13/0x20
 io_cqring_ev_posted+0x75/0xe0
v_posted at fs/io_uring.c:1160
 io_ring_ctx_wait_and_kill+0x1c0/0x2f0
l at fs/io_uring.c:7305
 io_uring_create+0xa8d/0x13b0
 ? io_req_defer_prep+0x990/0x990
 ? __kasan_check_write+0x14/0x20
 io_uring_setup+0xb8/0x130
 ? io_uring_create+0x13b0/0x13b0
 ? check_flags.part.28+0x220/0x220
 ? lockdep_hardirqs_on+0x16/0x2c0
 __x64_sys_io_uring_setup+0x31/0x40
 do_syscall_64+0xcc/0xaf0
 ? syscall_return_slowpath+0x580/0x580
 ? lockdep_hardirqs_off+0x1f/0x140
 ? entry_SYSCALL_64_after_hwframe+0x3e/0xb3
 ? trace_hardirqs_off_caller+0x3a/0x150
 ? trace_hardirqs_off_thunk+0x1a/0x1c
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x7fdcb9dd76ed
Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 6b 57 2c 00 f7 d8 64 89 01 48
RSP: 002b:00007ffe7fd4e4f8 EFLAGS: 00000246 ORIG_RAX: 00000000000001a9
RAX: ffffffffffffffda RBX: 00000000000001a9 RCX: 00007fdcb9dd76ed
RDX: fffffffffffffffc RSI: 0000000000000000 RDI: 0000000000005d54
RBP: 00000000000001a9 R08: 0000000e31d3caa7 R09: 0082400004004000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000002
R13: 00007fdcb842e058 R14: 00007fdcba4c46c0 R15: 00007fdcb842e000
Modules linked in: bridge stp llc nfnetlink cn brd vfat fat ext4 crc16 mbcache jbd2 loop kvm_intel kvm irqbypass intel_cstate intel_uncore dax_pmem intel_rapl_perf dax_pmem_core ip_tables x_tables xfs sd_mod tg3 firmware_class libphy hpsa scsi_transport_sas dm_mirror dm_region_hash dm_log dm_mod [last unloaded: binfmt_misc]
CR2: ffffffffffffffe8
---[ end trace f9502383d57e0e22 ]---
RIP: 0010:__wake_up_common+0x98/0x290
Code: 40 4d 8d 78 e8 49 8d 7f 18 49 39 fd 0f 84 80 00 00 00 e8 6b bd 2b 00 49 8b 5f 18 45 31 e4 48 83 eb 18 4c 89 ff e8 08 bc 2b 00 <45> 8b 37 41 f6 c6 04 75 71 49 8d 7f 10 e8 46 bd 2b 00 49 8b 47 10
RSP: 0018:ffffc9000adbfaf0 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffffffffffffffe8 RCX: ffffffffaa9636b8
RDX: 0000000000000003 RSI: dffffc0000000000 RDI: ffffffffffffffe8
RBP: ffffc9000adbfb40 R08: fffffbfff582c5fd R09: fffffbfff582c5fd
R10: ffffffffac162fe3 R11: fffffbfff582c5fc R12: 0000000000000000
R13: ffff888ef82b0960 R14: ffffc9000adbfb80 R15: ffffffffffffffe8
FS:  00007fdcba4c4740(0000) GS:ffff889033780000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffe8 CR3: 0000000f776a0004 CR4: 00000000001606e0
Kernel panic - not syncing: Fatal exception
Kernel Offset: 0x29800000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
---[ end Kernel panic - not syncing: Fatal exception ]—

which is due to error injection (or allocation failure) preventing the
rings from being setup. On shutdown, we attempt to remove any pending
requests, and for poll request, we call io_cqring_ev_posted() when we've
killed poll requests. However, since the rings aren't setup, we won't
find any poll requests. Make the calling of io_cqring_ev_posted()
dependent on actually having completed requests. This fixes this setup
corner case, and removes spurious calls if we remove poll requests and
don't find any.

Reported-by: Qian Cai <cai@lca.pw>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

8e2e1faf

io_uring: io_async_task_func() should check and honor cancelation · 2bae047e

Jens Axboe authored Apr 13, 2020



If the request has been marked as canceled, don't try and issue it.
Instead just fill a canceled event and finish the request.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

2bae047e

io_uring: check for need to re-wait in polled async handling · 74ce6ce4

Jens Axboe authored Apr 13, 2020

We added this for just the regular poll requests in commit a6ba632d


("io_uring: retry poll if we got woken with non-matching mask"), we
should do the same for the poll handler used pollable async requests.
Move the re-wait check and arm into a helper, and call it from
io_async_task_func() as well.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

74ce6ce4

Apr 13, 2020

io_uring: correct O_NONBLOCK check for splice punt · 88357580

Jens Axboe authored Apr 12, 2020

The splice file punt check uses file->f_mode to check for O_NONBLOCK,
but it should be checking file->f_flags. This leads to punting even
for files that have O_NONBLOCK set, which isn't necessary. This equates
to checking for FMODE_PATH, which will never be set on the fd in
question.

Fixes: 7d67af2c

 ("io_uring: add splice(2) support")
Signed-off-by: Jens Axboe <axboe@kernel.dk>

88357580

Apr 12, 2020

io_uring: restore req->work when canceling poll request · b1f573bd

Xiaoguang Wang authored Apr 12, 2020



When running liburing test case 'accept', I got below warning:
RED: Invalid credentials
RED: At include/linux/cred.h:285
RED: Specified credentials: 00000000d02474a0
RED: ->magic=4b, put_addr=000000005b4f46e9
RED: ->usage=-1699227648, subscr=-25693
RED: ->*uid = { 256,-25693,-25693,65534 }
RED: ->*gid = { 0,-1925859360,-1789740800,-1827028688 }
RED: ->security is 00000000258c136e
eneral protection fault, probably for non-canonical address 0xdead4ead00000000: 0000 [#1] SMP PTI
PU: 21 PID: 2037 Comm: accept Not tainted 5.6.0+ #318
ardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS rel-1.11.1-0-g0551a4be2c-prebuilt.qemu-project.org 04/01/2014
IP: 0010:dump_invalid_creds+0x16f/0x184
ode: 48 8b 83 88 00 00 00 48 3d ff 0f 00 00 76 29 48 89 c2 81 e2 00 ff ff ff 48
81 fa 00 6b 6b 6b 74 17 5b 48 c7 c7 4b b1 10 8e 5d <8b> 50 04 41 5c 8b 30 41 5d
e9 67 e3 04 00 5b 5d 41 5c 41 5d c3 0f
SP: 0018:ffffacc1039dfb38 EFLAGS: 00010087
AX: dead4ead00000000 RBX: ffff9ba39319c100 RCX: 0000000000000007
DX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8e10b14b
BP: ffffffff8e108476 R08: 0000000000000000 R09: 0000000000000001
10: 0000000000000000 R11: ffffacc1039df9e5 R12: 000000009552b900
13: 000000009319c130 R14: ffff9ba39319c100 R15: 0000000000000246
S:  00007f96b2bfc4c0(0000) GS:ffff9ba39f340000(0000) knlGS:0000000000000000
S:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
R2: 0000000000401870 CR3: 00000007db7a4000 CR4: 00000000000006e0
all Trace:
__invalid_creds+0x48/0x4a
__io_req_aux_free+0x2e8/0x3b0
? io_poll_remove_one+0x2a/0x1d0
__io_free_req+0x18/0x200
io_free_req+0x31/0x350
io_poll_remove_one+0x17f/0x1d0
io_poll_cancel.isra.80+0x6c/0x80
io_async_find_and_cancel+0x111/0x120
io_issue_sqe+0x181/0x10e0
? __lock_acquire+0x552/0xae0
? lock_acquire+0x8e/0x310
? fs_reclaim_acquire.part.97+0x5/0x30
__io_queue_sqe.part.100+0xc4/0x580
? io_submit_sqes+0x751/0xbd0
? rcu_read_lock_sched_held+0x32/0x40
io_submit_sqes+0x9ba/0xbd0
? __x64_sys_io_uring_enter+0x2b2/0x460
? __x64_sys_io_uring_enter+0xaf/0x460
? find_held_lock+0x2d/0x90
? __x64_sys_io_uring_enter+0x111/0x460
__x64_sys_io_uring_enter+0x2d7/0x460
do_syscall_64+0x5a/0x230
entry_SYSCALL_64_after_hwframe+0x49/0xb3

After looking into codes, it turns out that this issue is because we didn't
restore the req->work, which is changed in io_arm_poll_handler(), req->work
is a union with below struct:
	struct {
		struct callback_head	task_work;
		struct hlist_node	hash_node;
		struct async_poll	*apoll;
	};
If we forget to restore, members in struct io_wq_work would be invalid,
restore the req->work to fix this issue.

Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

Get rid of not needed 'need_restore' variable.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

b1f573bd

io_uring: move all request init code in one place · ef4ff581

Pavel Begunkov authored Apr 12, 2020



Requests initialisation is scattered across several functions, namely
io_init_req(), io_submit_sqes(), io_submit_sqe(). Put it
in io_init_req() for better data locality and code clarity.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

ef4ff581

io_uring: keep all sqe->flags in req->flags · dea3b49c

Pavel Begunkov authored Apr 12, 2020



It's a good idea to not read sqe->flags twice, as it's prone to security
bugs. Instead of passing it around, embeed them in req->flags. It's
already so except for IOSQE_IO_LINK.
1. rename former REQ_F_LINK -> REQ_F_LINK_HEAD
2. introduce and copy REQ_F_LINK, which mimics IO_IOSQE_LINK

And leave req_set_fail_links() using new REQ_F_LINK, because it's more
sensible.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

dea3b49c

io_uring: early submission req fail code · 1d4240cc

Pavel Begunkov authored Apr 12, 2020



Having only one place for cleaning up a request after a link assembly/
submission failure will play handy in the future. At least it allows
to remove duplicated cleanup sequence.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1d4240cc

io_uring: track mm through current->mm · bf9c2f1c

Pavel Begunkov authored Apr 12, 2020



As a preparation for extracting request init bits, remove self-coded mm
tracking from io_submit_sqes(), but rely on current->mm. It's more
convenient, than passing this piece of state in other functions.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

bf9c2f1c

io_uring: remove obsolete @mm_fault · dccc587f

Pavel Begunkov authored Apr 12, 2020



If io_submit_sqes() can't grab an mm, it fails and exits right away.
There is no need to track the fact of the failure. Remove @mm_fault.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

dccc587f

Apr 11, 2020

Merge branch 'akpm' (patches from Andrew) · 5b8b9d0c

Linus Torvalds authored Apr 10, 2020

Merge yet more updates from Andrew Morton:

 - Almost all of the rest of MM (memcg, slab-generic, slab, pagealloc,
   gup, hugetlb, pagemap, memremap)

 - Various other things (hfs, ocfs2, kmod, misc, seqfile)

* akpm: (34 commits)
  ipc/util.c: sysvipc_find_ipc() should increase position index
  kernel/gcov/fs.c: gcov_seq_next() should increase position index
  fs/seq_file.c: seq_read(): add info message about buggy .next functions
  drivers/dma/tegra20-apb-dma.c: fix platform_get_irq.cocci warnings
  change email address for Pali Rohár
  selftests: kmod: test disabling module autoloading
  selftests: kmod: fix handling test numbers above 9
  docs: admin-guide: document the kernel.modprobe sysctl
  fs/filesystems.c: downgrade user-reachable WARN_ONCE() to pr_warn_once()
  kmod: make request_module() return an error when autoloading is disabled
  mm/memremap: set caching mode for PCI P2PDMA memory to WC
  mm/memory_hotplug: add pgprot_t to mhp_params
  powerpc/mm: thread pgprot_t through create_section_mapping()
  x86/mm: introduce __set_memory_prot()
  x86/mm: thread pgprot_t through init_memory_mapping()
  mm/memory_hotplug: rename mhp_restrictions to mhp_params
  mm/memory_hotplug: drop the flags field from struct mhp_restrictions
  mm/special: create generic fallbacks for pte_special() and pte_mkspecial()
  mm/vma: introduce VM_ACCESS_FLAGS
  mm/vma: define a default value for VM_DATA_DEFAULT_FLAGS
  ...

5b8b9d0c

Merge tag 'docs-5.7-2' of git://git.lwn.net/linux · ca6151a9

Linus Torvalds authored Apr 10, 2020

Pull Documentation fixes from Jonathan Corbet:
 "A handful of late-arriving fixes for the documentation tree"

* tag 'docs-5.7-2' of git://git.lwn.net/linux:
  Documentation: android: binderfs: add 'stats' mount option
  Documentation: driver-api/usb/writing_usb_driver.rst Updates documentation links
  docs: driver-api: address duplicate label warning
  Documentation: sysrq: fix RST formatting
  docs: kernel-parameters.txt: Fix broken references
  docs: kernel-parameters.txt: Remove nompx
  docs: filesystems: fix typo in qnx6.rst

ca6151a9

Merge tag 'for-linus-5.7-ofs1' of git://git.kernel.org/pub/scm/linux/kernel/git/hubcap/linux · 4e4bdcfa

Linus Torvalds authored Apr 10, 2020

Pull orangefs updates from Mike Marshall:
 "A fix and two cleanups.

  Fix:

   - Christoph Hellwig noticed that some logic I added to
     orangefs_file_read_iter introduced a race condition, so he sent a
     reversion patch. I had to modify his patch since reverting at this
     point broke Orangefs.

  Cleanups:

   - Christoph Hellwig noticed that we were doing some unnecessary work
     in orangefs_flush, so he sent in a patch that removed the un-needed
     code.

   - Al Viro told me he had trouble building Orangefs. Orangefs should
     be easy to build, even for Al :-).

     I looked back at the test server build notes in orangefs.txt, just
     in case that's where the trouble really is, and found a couple of
     typos and made a couple of clarifications"

* tag 'for-linus-5.7-ofs1' of git://git.kernel.org/pub/scm/linux/kernel/git/hubcap/linux:
  orangefs: clarify build steps for test server in orangefs.txt
  orangefs: don't mess with I_DIRTY_TIMES in orangefs_flush
  orangefs: get rid of knob code...

4e4bdcfa

Merge tag 'xtensa-20200410' of git://github.com/jcmvbkbc/linux-xtensa · 9539303a

Linus Torvalds authored Apr 10, 2020

Pull xtensa updates from Max Filippov:

 - replace setup_irq() by request_irq()

 - cosmetic fixes in xtensa Kconfig and boot/Makefile

* tag 'xtensa-20200410' of git://github.com/jcmvbkbc/linux-xtensa:
  arch/xtensa: fix grammar in Kconfig help text
  xtensa: remove meaningless export ccflags-y
  xtensa: replace setup_irq() by request_irq()

9539303a

Merge tag 'for-linus-5.7-rc1b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip · e6383b18

Linus Torvalds authored Apr 10, 2020

Pull more xen updates from Juergen Gross:

 - two cleanups

 - fix a boot regression introduced in this merge window

 - fix wrong use of memory allocation flags

* tag 'for-linus-5.7-rc1b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  x86/xen: fix booting 32-bit pv guest
  x86/xen: make xen_pvmmu_arch_setup() static
  xen/blkfront: fix memory allocation flags in blkfront_setup_indirect()
  xen: Use evtchn_type_t as a type for event channels

e6383b18

ipc/util.c: sysvipc_find_ipc() should increase position index · 89163f93

Vasily Averin authored Apr 10, 2020

If seq_file .next function does not change position index, read after
some lseek can generate unexpected output.

https://bugzilla.kernel.org/show_bug.cgi?id=206283


Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Waiman Long <longman@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: NeilBrown <neilb@suse.com>
Cc: Peter Oberparleiter <oberpar@linux.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/b7a20945-e315-8bb0-21e6-3875c14a8494@virtuozzo.com


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

89163f93

kernel/gcov/fs.c: gcov_seq_next() should increase position index · f4d74ef6

Vasily Averin authored Apr 10, 2020

If seq_file .next function does not change position index, read after
some lseek can generate unexpected output.

https://bugzilla.kernel.org/show_bug.cgi?id=206283


Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: NeilBrown <neilb@suse.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Waiman Long <longman@redhat.com>
Link: http://lkml.kernel.org/r/f65c6ee7-bd00-f910-2f8a-37cc67e4ff88@virtuozzo.com


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

f4d74ef6

fs/seq_file.c: seq_read(): add info message about buggy .next functions · 3bfa7e14

Vasily Averin authored Apr 10, 2020

Patch series "seq_file .next functions should increase position index".

In Aug 2018 NeilBrown noticed commit 1f4aace6 ("fs/seq_file.c:
simplify seq_file iteration code and interface")

"Some ->next functions do not increment *pos when they return NULL...
Note that such ->next functions are buggy and should be fixed.  A simple
demonstration is dd if=/proc/swaps bs=1000 skip=1 Choose any block size
larger than the size of /proc/swaps.  This will always show the whole
last line of /proc/swaps"

Described problem is still actual.  If you make lseek into middle of
last output line following read will output end of last line and whole
last line once again.

  $ dd if=/proc/swaps bs=1  # usual output
  Filename				Type		Size	Used	Priority
  /dev/dm-0                             partition	4194812	97536	-2
  104+0 records in
  104+0 records out
  104 bytes copied

  $ dd if=/proc/swaps bs=40 skip=1    # last line was generated twice
  dd: /proc/swaps: cannot skip to specified offset
  v/dm-0                                partition	4194812	97536	-2
  /dev/dm-0                             partition	4194812	97536	-2
  3+1 records in
  3+1 records out
  131 bytes copied

There are lot of other affected files, I've found 30+ including
/proc/net/ip_tables_matches and /proc/sysvipc/*

I've sent patches into maillists of affected subsystems already, this
patch-set fixes the problem in files related to pstore, tracing, gcov,
sysvipc and other subsystems processed via linux-kernel@ mailing list
directly

https://bugzilla.kernel.org/show_bug.cgi?id=206283

This patch (of 4):

Add debug code to seq_read() to detect missed or out-of-tree incorrect
.next seq_file functions.

[akpm@linux-foundation.org: s/pr_info/pr_info_ratelimited/, per Qian Cai]
https://bugzilla.kernel.org/show_bug.cgi?id=206283


Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: NeilBrown <neilb@suse.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Peter Oberparleiter <oberpar@linux.ibm.com>
Cc: Waiman Long <longman@redhat.com>
Link: http://lkml.kernel.org/r/244674e5-760c-86bd-d08a-047042881748@virtuozzo.com
Link: http://lkml.kernel.org/r/7c24087c-e280-e580-5b0c-0cdaeb14cd18@virtuozzo.com


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3bfa7e14

drivers/dma/tegra20-apb-dma.c: fix platform_get_irq.cocci warnings · cb8d9937

kbuild test robot authored Apr 10, 2020

Remove dev_err() messages after platform_get_irq*() failures.
platform_get_irq() already prints an error.

Generated by: scripts/coccinelle/api/platform_get_irq.cocci

Fixes: 6c41ac96

 ("dmaengine: tegra-apb: Support COMPILE_TEST")
Signed-off-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Julia Lawall <julia.lawall@inria.fr>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Cc: Laxman Dewangan <ldewangan@nvidia.com>
Cc: Vinod Koul <vinod.koul@linux.intel.com>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Jon Hunter <jonathanh@nvidia.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.21.2002271133450.2973@hadrien


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

cb8d9937

change email address for Pali Rohár · 149ed3d4

Pali Rohár authored Apr 10, 2020



For security reasons I stopped using gmail account and kernel address is
now up-to-date alias to my personal address.

People periodically send me emails to address which they found in source
code of drivers, so this change reflects state where people can contact
me.

[ Added .mailmap entry as per Joe Perches  - Linus ]
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Joe Perches <joe@perches.com>
Link: http://lkml.kernel.org/r/20200307104237.8199-1-pali@kernel.org


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

149ed3d4

selftests: kmod: test disabling module autoloading · 23756e55

Eric Biggers authored Apr 10, 2020



Test that request_module() fails with -ENOENT when
/proc/sys/kernel/modprobe contains (a) a nonexistent path, and (b) an
empty path.

Case (b) is a regression test for the patch "kmod: make request_module()
return an error when autoloading is disabled".

Tested with 'kmod.sh -t 0010 && kmod.sh -t 0011', and also simply with
'kmod.sh' to run all kmod tests.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jeff Vander Stoep <jeffv@google.com>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: NeilBrown <neilb@suse.com>
Link: http://lkml.kernel.org/r/20200312202552.241885-5-ebiggers@kernel.org


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

23756e55

selftests: kmod: fix handling test numbers above 9 · 6d573a07

Eric Biggers authored Apr 10, 2020



get_test_count() and get_test_enabled() were broken for test numbers
above 9 due to awk interpreting a field specification like '$0010' as
octal rather than decimal.  Fix it by stripping the leading zeroes.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jeff Vander Stoep <jeffv@google.com>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: NeilBrown <neilb@suse.com>
Link: http://lkml.kernel.org/r/20200318230515.171692-5-ebiggers@kernel.org


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

6d573a07

docs: admin-guide: document the kernel.modprobe sysctl · 6e715825

Eric Biggers authored Apr 10, 2020

Document the kernel.modprobe sysctl in the same place that all the other
kernel.* sysctls are documented.  Make sure to mention how to use this
sysctl to completely disable module autoloading, and how this sysctl
relates to CONFIG_STATIC_USERMODEHELPER.

[ebiggers@google.com: v5]
  Link: http://lkml.kernel.org/r/20200318230515.171692-4-ebiggers@kernel.org


Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jeff Vander Stoep <jeffv@google.com>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: NeilBrown <neilb@suse.com>
Link: http://lkml.kernel.org/r/20200312202552.241885-4-ebiggers@kernel.org


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

6e715825

fs/filesystems.c: downgrade user-reachable WARN_ONCE() to pr_warn_once() · 26c5d78c

Eric Biggers authored Apr 10, 2020

After request_module(), nothing is stopping the module from being
unloaded until someone takes a reference to it via try_get_module().

The WARN_ONCE() in get_fs_type() is thus user-reachable, via userspace
running 'rmmod' concurrently.

Since WARN_ONCE() is for kernel bugs only, not for user-reachable
situations, downgrade this warning to pr_warn_once().

Keep it printed once only, since the intent of this warning is to detect
a bug in modprobe at boot time.  Printing the warning more than once
wouldn't really provide any useful extra information.

Fixes: 41124db8

 ("fs: warn in case userspace lied about modprobe return")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jessica Yu <jeyu@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jeff Vander Stoep <jeffv@google.com>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: NeilBrown <neilb@suse.com>
Cc: <stable@vger.kernel.org>		[4.13+]
Link: http://lkml.kernel.org/r/20200312202552.241885-3-ebiggers@kernel.org


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

26c5d78c

kmod: make request_module() return an error when autoloading is disabled · d7d27cfc

Eric Biggers authored Apr 10, 2020

Patch series "module autoloading fixes and cleanups", v5.

This series fixes a bug where request_module() was reporting success to
kernel code when module autoloading had been completely disabled via
'echo > /proc/sys/kernel/modprobe'.

It also addresses the issues raised on the original thread
(https://lkml.kernel.org/lkml/20200310223731.126894-1-ebiggers@kernel.org/T/#u

)
bydocumenting the modprobe sysctl, adding a self-test for the empty path
case, and downgrading a user-reachable WARN_ONCE().

This patch (of 4):

It's long been possible to disable kernel module autoloading completely
(while still allowing manual module insertion) by setting
/proc/sys/kernel/modprobe to the empty string.

This can be preferable to setting it to a nonexistent file since it
avoids the overhead of an attempted execve(), avoids potential
deadlocks, and avoids the call to security_kernel_module_request() and
thus on SELinux-based systems eliminates the need to write SELinux rules
to dontaudit module_request.

However, when module autoloading is disabled in this way,
request_module() returns 0.  This is broken because callers expect 0 to
mean that the module was successfully loaded.

Apparently this was never noticed because this method of disabling
module autoloading isn't used much, and also most callers don't use the
return value of request_module() since it's always necessary to check
whether the module registered its functionality or not anyway.

But improperly returning 0 can indeed confuse a few callers, for example
get_fs_type() in fs/filesystems.c where it causes a WARNING to be hit:

	if (!fs && (request_module("fs-%.*s", len, name) == 0)) {
		fs = __get_fs_type(name, len);
		WARN_ONCE(!fs, "request_module fs-%.*s succeeded, but still no fs?\n", len, name);
	}

This is easily reproduced with:

	echo > /proc/sys/kernel/modprobe
	mount -t NONEXISTENT none /

It causes:

	request_module fs-NONEXISTENT succeeded, but still no fs?
	WARNING: CPU: 1 PID: 1106 at fs/filesystems.c:275 get_fs_type+0xd6/0xf0
	[...]

This should actually use pr_warn_once() rather than WARN_ONCE(), since
it's also user-reachable if userspace immediately unloads the module.
Regardless, request_module() should correctly return an error when it
fails.  So let's make it return -ENOENT, which matches the error when
the modprobe binary doesn't exist.

I've also sent patches to document and test this case.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Jessica Yu <jeyu@kernel.org>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jeff Vander Stoep <jeffv@google.com>
Cc: Ben Hutchings <benh@debian.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200310223731.126894-1-ebiggers@kernel.org
Link: http://lkml.kernel.org/r/20200312202552.241885-1-ebiggers@kernel.org


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

d7d27cfc

mm/memremap: set caching mode for PCI P2PDMA memory to WC · a50d8d98

Logan Gunthorpe authored Apr 10, 2020



PCI BAR IO memory should never be mapped as WB, however prior to this
the PAT bits were set WB and it was typically overridden by MTRR
registers set by the firmware.

Set PCI P2PDMA memory to be UC as this is what it currently, typically,
ends up being mapped as on x86 after the MTRR registers override the
cache setting.

Future use-cases may need to generalize this by adding flags to select
the caching type, as some P2PDMA cases may not want UC.  However, those
use-cases are not upstream yet and this can be changed when they arrive.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Eric Badger <ebadger@gigaio.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/20200306170846.9333-8-logang@deltatee.com


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

a50d8d98

mm/memory_hotplug: add pgprot_t to mhp_params · bfeb022f

Logan Gunthorpe authored Apr 10, 2020



devm_memremap_pages() is currently used by the PCI P2PDMA code to create
struct page mappings for IO memory.  At present, these mappings are
created with PAGE_KERNEL which implies setting the PAT bits to be WB.
However, on x86, an mtrr register will typically override this and force
the cache type to be UC-.  In the case firmware doesn't set this
register it is effectively WB and will typically result in a machine
check exception when it's accessed.

Other arches are not currently likely to function correctly seeing they
don't have any MTRR registers to fall back on.

To solve this, provide a way to specify the pgprot value explicitly to
arch_add_memory().

Of the arches that support MEMORY_HOTPLUG: x86_64, and arm64 need a
simple change to pass the pgprot_t down to their respective functions
which set up the page tables.  For x86_32, set the page tables
explicitly using _set_memory_prot() (seeing they are already mapped).

For ia64, s390 and sh, reject anything but PAGE_KERNEL settings -- this
should be fine, for now, seeing these architectures don't support
ZONE_DEVICE.

A check in __add_pages() is also added to ensure the pgprot parameter
was set for all arches.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Badger <ebadger@gigaio.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/20200306170846.9333-7-logang@deltatee.com


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

bfeb022f

powerpc/mm: thread pgprot_t through create_section_mapping() · 4e00c5af

Logan Gunthorpe authored Apr 10, 2020

In prepartion to support a pgprot_t argument for arch_add_memory().

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Eric Badger <ebadger@gigaio.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/20200306170846.9333-6-logang@deltatee.com

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4e00c5af

x86/mm: introduce __set_memory_prot() · 30796e18

Logan Gunthorpe authored Apr 10, 2020

For use in the 32bit arch_add_memory() to set the pgprot type of the
memory to add.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Eric Badger <ebadger@gigaio.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/20200306170846.9333-5-logang@deltatee.com

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

30796e18