user/sven/linux.git/fs, branch v5.15.8

aio: Fix incorrect usage of eventfd_signal_allowed()

2021-12-14T09:57:22Z

commit 4b3749865374899e115aa8c48681709b086fe6d3 upstream. We should defer eventfd_signal() to the workqueue when eventfd_signal_allowed() return false rather than return true. Fixes: b542e383d8c0 ("eventfd: Make signal recursion protection a task bit") Signed-off-by: Xie Yongji Link: https://lore.kernel.org/r/20210913111928.98-1-xieyongji@bytedance.com Reviewed-by: Eric Biggers Signed-off-by: Eric Biggers Signed-off-by: Greg Kroah-Hartman

tracefs: Set all files to the same group ownership as the mount option

2021-12-14T09:57:15Z

commit 48b27b6b5191e2e1f2798cd80877b6e4ef47c351 upstream. As people have been asking to allow non-root processes to have access to the tracefs directory, it was considered best to only allow groups to have access to the directory, where it is easier to just set the tracefs file system to a specific group (as other would be too dangerous), and that way the admins could pick which processes would have access to tracefs. Unfortunately, this broke tooling on Android that expected the other bit to be set. For some special cases, for non-root tools to trace the system, tracefs would be mounted and change the permissions of the top level directory which gave access to all running tasks permission to the tracing directory. Even though this would be dangerous to do in a production environment, for testing environments this can be useful. Now with the new changes to not allow other (which is still the proper thing to do), it breaks the testing tooling. Now more code needs to be loaded on the system to change ownership of the tracing directory. The real solution is to have tracefs honor the gid=xxx option when mounting. That is, (tracing group tracing has value 1003) mount -t tracefs -o gid=1003 tracefs /sys/kernel/tracing should have it that all files in the tracing directory should be of the given group. Copy the logic from d_walk() from dcache.c and simplify it for the mount case of tracefs if gid is set. All the files in tracefs will be walked and their group will be set to the value passed in. Link: https://lkml.kernel.org/r/20211207171729.2a54e1b3@gandalf.local.home Cc: Ingo Molnar Cc: Kees Cook Cc: Andrew Morton Cc: Linus Torvalds Cc: linux-fsdevel@vger.kernel.org Cc: Al Viro Cc: Greg Kroah-Hartman Reported-by: Kalesh Singh Reported-by: Yabin Cui Fixes: 49d67e445742 ("tracefs: Have tracefs directories not set OTH permission bits by default") Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman

aio: fix use-after-free due to missing POLLFREE handling

2021-12-14T09:57:15Z

commit 50252e4b5e989ce64555c7aef7516bdefc2fea72 upstream. signalfd_poll() and binder_poll() are special in that they use a waitqueue whose lifetime is the current task, rather than the struct file as is normally the case. This is okay for blocking polls, since a blocking poll occurs within one task; however, non-blocking polls require another solution. This solution is for the queue to be cleared before it is freed, by sending a POLLFREE notification to all waiters. Unfortunately, only eventpoll handles POLLFREE. A second type of non-blocking poll, aio poll, was added in kernel v4.18, and it doesn't handle POLLFREE. This allows a use-after-free to occur if a signalfd or binder fd is polled with aio poll, and the waitqueue gets freed. Fix this by making aio poll handle POLLFREE. A patch by Ramji Jiyani (https://lore.kernel.org/r/20211027011834.2497484-1-ramjiyani@google.com) tried to do this by making aio_poll_wake() always complete the request inline if POLLFREE is seen. However, that solution had two bugs. First, it introduced a deadlock, as it unconditionally locked the aio context while holding the waitqueue lock, which inverts the normal locking order. Second, it didn't consider that POLLFREE notifications are missed while the request has been temporarily de-queued. The second problem was solved by my previous patch. This patch then properly fixes the use-after-free by handling POLLFREE in a deadlock-free way. It does this by taking advantage of the fact that freeing of the waitqueue is RCU-delayed, similar to what eventpoll does. Fixes: 2c14fa838cbe ("aio: implement IOCB_CMD_POLL") Cc: # v4.18+ Link: https://lore.kernel.org/r/20211209010455.42744-6-ebiggers@kernel.org Signed-off-by: Eric Biggers Signed-off-by: Greg Kroah-Hartman

aio: keep poll requests on waitqueue until completed

2021-12-14T09:57:15Z

commit 363bee27e25804d8981dd1c025b4ad49dc39c530 upstream. Currently, aio_poll_wake() will always remove the poll request from the waitqueue. Then, if aio_poll_complete_work() sees that none of the polled events are ready and the request isn't cancelled, it re-adds the request to the waitqueue. (This can easily happen when polling a file that doesn't pass an event mask when waking up its waitqueue.) This is fundamentally broken for two reasons: 1. If a wakeup occurs between vfs_poll() and the request being re-added to the waitqueue, it will be missed because the request wasn't on the waitqueue at the time. Therefore, IOCB_CMD_POLL might never complete even if the polled file is ready. 2. When the request isn't on the waitqueue, there is no way to be notified that the waitqueue is being freed (which happens when its lifetime is shorter than the struct file's). This is supposed to happen via the waitqueue entries being woken up with POLLFREE. Therefore, leave the requests on the waitqueue until they are actually completed (or cancelled). To keep track of when aio_poll_complete_work needs to be scheduled, use new fields in struct poll_iocb. Remove the 'done' field which is now redundant. Note that this is consistent with how sys_poll() and eventpoll work; their wakeup functions do *not* remove the waitqueue entries. Fixes: 2c14fa838cbe ("aio: implement IOCB_CMD_POLL") Cc: # v4.18+ Link: https://lore.kernel.org/r/20211209010455.42744-5-ebiggers@kernel.org Signed-off-by: Eric Biggers Signed-off-by: Greg Kroah-Hartman

signalfd: use wake_up_pollfree()

2021-12-14T09:57:15Z

commit 9537bae0da1f8d1e2361ab6d0479e8af7824e160 upstream. wake_up_poll() uses nr_exclusive=1, so it's not guaranteed to wake up all exclusive waiters. Yet, POLLFREE *must* wake up all waiters. epoll and aio poll are fortunately not affected by this, but it's very fragile. Thus, the new function wake_up_pollfree() has been introduced. Convert signalfd to use wake_up_pollfree(). Reported-by: Linus Torvalds Fixes: d80e731ecab4 ("epoll: introduce POLLFREE to flush ->signalfd_wqh before kfree()") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20211209010455.42744-4-ebiggers@kernel.org Signed-off-by: Eric Biggers Signed-off-by: Greg Kroah-Hartman

io_uring: ensure task_work gets run as part of cancelations

2021-12-14T09:57:15Z

commit 78a780602075d8b00c98070fa26e389b3b3efa72 upstream. If we successfully cancel a work item but that work item needs to be processed through task_work, then we can be sleeping uninterruptibly in io_uring_cancel_generic() and never process it. Hence we don't make forward progress and we end up with an uninterruptible sleep warning. While in there, correct a comment that should be IFF, not IIF. Reported-and-tested-by: syzbot+21e6887c0be14181206d@syzkaller.appspotmail.com Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

tracefs: Have new files inherit the ownership of their parent

2021-12-14T09:57:14Z

commit ee7f3666995d8537dec17b1d35425f28877671a9 upstream. If directories in tracefs have their ownership changed, then any new files and directories that are created under those directories should inherit the ownership of the director they are created in. Link: https://lkml.kernel.org/r/20211208075720.4855d180@gandalf.local.home Cc: Kees Cook Cc: Ingo Molnar Cc: Andrew Morton Cc: Linus Torvalds Cc: Al Viro Cc: Greg Kroah-Hartman Cc: Yabin Cui Cc: Christian Brauner Cc: stable@vger.kernel.org Fixes: 4282d60689d4f ("tracefs: Add new tracefs file system") Reported-by: Kalesh Singh Reported: https://lore.kernel.org/all/CAC_TJve8MMAv+H_NdLSJXZUSoxOEq2zB_pVaJ9p=7H6Bu3X76g@mail.gmail.com/ Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman

nfsd: Fix nsfd startup race (again)

2021-12-14T09:57:14Z

commit b10252c7ae9c9d7c90552f88b544a44ee773af64 upstream. Commit bd5ae9288d64 ("nfsd: register pernet ops last, unregister first") has re-opened rpc_pipefs_event() race against nfsd_net_id registration (register_pernet_subsys()) which has been fixed by commit bb7ffbf29e76 ("nfsd: fix nsfd startup race triggering BUG_ON"). Restore the order of register_pernet_subsys() vs register_cld_notifier(). Add WARN_ON() to prevent a future regression. Crash info: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000012 CPU: 8 PID: 345 Comm: mount Not tainted 5.4.144-... #1 pc : rpc_pipefs_event+0x54/0x120 [nfsd] lr : rpc_pipefs_event+0x48/0x120 [nfsd] Call trace: rpc_pipefs_event+0x54/0x120 [nfsd] blocking_notifier_call_chain rpc_fill_super get_tree_keyed rpc_fs_get_tree vfs_get_tree do_mount ksys_mount __arm64_sys_mount el0_svc_handler el0_svc Fixes: bd5ae9288d64 ("nfsd: register pernet ops last, unregister first") Cc: stable@vger.kernel.org Signed-off-by: Alexander Sverdlin Signed-off-by: J. Bruce Fields Signed-off-by: Greg Kroah-Hartman

nfsd: fix use-after-free due to delegation race

2021-12-14T09:57:14Z

commit 548ec0805c399c65ed66c6641be467f717833ab5 upstream. A delegation break could arrive as soon as we've called vfs_setlease. A delegation break runs a callback which immediately (in nfsd4_cb_recall_prepare) adds the delegation to del_recall_lru. If we then exit nfs4_set_delegation without hashing the delegation, it will be freed as soon as the callback is done with it, without ever being removed from del_recall_lru. Symptoms show up later as use-after-free or list corruption warnings, usually in the laundromat thread. I suspect aba2072f4523 "nfsd: grant read delegations to clients holding writes" made this bug easier to hit, but I looked as far back as v3.0 and it looks to me it already had the same problem. So I'm not sure where the bug was introduced; it may have been there from the beginning. Cc: stable@vger.kernel.org Signed-off-by: J. Bruce Fields Signed-off-by: Greg Kroah-Hartman

btrfs: free exchange changeset on failures

2021-12-14T09:57:13Z

commit da5e817d9d75422eaaa05490d0b9a5e328fc1a51 upstream. Fstests runs on my VMs have show several kmemleak reports like the following. unreferenced object 0xffff88811ae59080 (size 64): comm "xfs_io", pid 12124, jiffies 4294987392 (age 6.368s) hex dump (first 32 bytes): 00 c0 1c 00 00 00 00 00 ff cf 1c 00 00 00 00 00 ................ 90 97 e5 1a 81 88 ff ff 90 97 e5 1a 81 88 ff ff ................ backtrace: [<00000000ac0176d2>] ulist_add_merge+0x60/0x150 [btrfs] [<0000000076e9f312>] set_state_bits+0x86/0xc0 [btrfs] [<0000000014fe73d6>] set_extent_bit+0x270/0x690 [btrfs] [<000000004f675208>] set_record_extent_bits+0x19/0x20 [btrfs] [<00000000b96137b1>] qgroup_reserve_data+0x274/0x310 [btrfs] [<0000000057e9dcbb>] btrfs_check_data_free_space+0x5c/0xa0 [btrfs] [<0000000019c4511d>] btrfs_delalloc_reserve_space+0x1b/0xa0 [btrfs] [<000000006d37e007>] btrfs_dio_iomap_begin+0x415/0x970 [btrfs] [<00000000fb8a74b8>] iomap_iter+0x161/0x1e0 [<0000000071dff6ff>] __iomap_dio_rw+0x1df/0x700 [<000000002567ba53>] iomap_dio_rw+0x5/0x20 [<0000000072e555f8>] btrfs_file_write_iter+0x290/0x530 [btrfs] [<000000005eb3d845>] new_sync_write+0x106/0x180 [<000000003fb505bf>] vfs_write+0x24d/0x2f0 [<000000009bb57d37>] __x64_sys_pwrite64+0x69/0xa0 [<000000003eba3fdf>] do_syscall_64+0x43/0x90 In case brtfs_qgroup_reserve_data() or btrfs_delalloc_reserve_metadata() fail the allocated extent_changeset will not be freed. So in btrfs_check_data_free_space() and btrfs_delalloc_reserve_space() free the allocated extent_changeset to get rid of the allocated memory. The issue currently only happens in the direct IO write path, but only after 65b3c08606e5 ("btrfs: fix ENOSPC failure when attempting direct IO write into NOCOW range"), and also at defrag_one_locked_target(). Every other place is always calling extent_changeset_free() even if its call to btrfs_delalloc_reserve_space() or btrfs_check_data_free_space() has failed. CC: stable@vger.kernel.org # 5.15+ Reviewed-by: Filipe Manana Signed-off-by: Johannes Thumshirn Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman