From 6e356d45950e2d26b63531a2fd112c987da7a933 Mon Sep 17 00:00:00 2001 From: Mike Marshall Date: Tue, 5 Feb 2019 14:13:34 -0500 Subject: orangefs: remove two un-needed BUG_ONs... Signed-off-by: Mike Marshall --- fs/orangefs/file.c | 4 ---- 1 file changed, 4 deletions(-) (limited to 'fs') diff --git a/fs/orangefs/file.c b/fs/orangefs/file.c index a5a2fe76568f..b094d3d79354 100644 --- a/fs/orangefs/file.c +++ b/fs/orangefs/file.c @@ -398,8 +398,6 @@ static ssize_t orangefs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter loff_t pos = iocb->ki_pos; ssize_t rc = 0; - BUG_ON(iocb->private); - gossip_debug(GOSSIP_FILE_DEBUG, "orangefs_file_read_iter\n"); orangefs_stats.reads++; @@ -416,8 +414,6 @@ static ssize_t orangefs_file_write_iter(struct kiocb *iocb, struct iov_iter *ite loff_t pos; ssize_t rc; - BUG_ON(iocb->private); - gossip_debug(GOSSIP_FILE_DEBUG, "orangefs_file_write_iter\n"); inode_lock(file->f_mapping->host); -- cgit From 53a41cb7ed381edee91029cdcabe9b3250f43f4d Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Mon, 25 Feb 2019 09:10:51 -0800 Subject: Revert "x86/fault: BUG() when uaccess helpers fault on kernel addresses" MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This reverts commit 9da3f2b74054406f87dff7101a569217ffceb29b. It was well-intentioned, but wrong. Overriding the exception tables for instructions for random reasons is just wrong, and that is what the new code did. It caused problems for tracing, and it caused problems for strncpy_from_user(), because the new checks made perfectly valid use cases break, rather than catch things that did bad things. Unchecked user space accesses are a problem, but that's not a reason to add invalid checks that then people have to work around with silly flags (in this case, that 'kernel_uaccess_faults_ok' flag, which is just an odd way to say "this commit was wrong" and was sprinked into random places to hide the wrongness). The real fix to unchecked user space accesses is to get rid of the special "let's not check __get_user() and __put_user() at all" logic. Make __{get|put}_user() be just aliases to the regular {get|put}_user() functions, and make it impossible to access user space without having the proper checks in places. The raison d'être of the special double-underscore versions used to be that the range check was expensive, and if you did multiple user accesses, you'd do the range check up front (like the signal frame handling code, for example). But SMAP (on x86) and PAN (on ARM) have made that optimization pointless, because the _real_ expense is the "set CPU flag to allow user space access". Do let's not break the valid cases to catch invalid cases that shouldn't even exist. Cc: Thomas Gleixner Cc: Kees Cook Cc: Tobin C. Harding Cc: Borislav Petkov Cc: Peter Zijlstra Cc: Andy Lutomirski Cc: Jann Horn Signed-off-by: Linus Torvalds --- fs/namespace.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'fs') diff --git a/fs/namespace.c b/fs/namespace.c index a677b59efd74..678ef175d63a 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -2698,7 +2698,6 @@ static long exact_copy_from_user(void *to, const void __user * from, if (!access_ok(from, n)) return n; - current->kernel_uaccess_faults_ok++; while (n) { if (__get_user(c, f)) { memset(t, 0, n); @@ -2708,7 +2707,6 @@ static long exact_copy_from_user(void *to, const void __user * from, f++; n--; } - current->kernel_uaccess_faults_ok--; return n; } -- cgit From 7d762d69145a54d169f58e56d6dac57a5508debc Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 21 Feb 2019 22:04:32 +0000 Subject: afs: Fix manually set volume location server list When a cell with a volume location server list is added manually by echoing the details into /proc/net/afs/cells, a record is added but the flag saying it has been looked up isn't set. This causes the VL server rotation code to wait forever, with the top of /proc/pid/stack looking like: afs_select_vlserver+0x3a6/0x6f3 afs_vl_lookup_vldb+0x4b/0x92 afs_create_volume+0x25/0x1b9 ... with the thread stuck in afs_start_vl_iteration() waiting for AFS_CELL_FL_NO_LOOKUP_YET to be cleared. Fix this by clearing AFS_CELL_FL_NO_LOOKUP_YET when setting up a record if that record's details were supplied manually. Fixes: 0a5143f2f89c ("afs: Implement VL server rotation") Reported-by: Dave Botsch Signed-off-by: David Howells Signed-off-by: Linus Torvalds --- fs/afs/cell.c | 1 + 1 file changed, 1 insertion(+) (limited to 'fs') diff --git a/fs/afs/cell.c b/fs/afs/cell.c index cf445dbd5f2e..9de46116c749 100644 --- a/fs/afs/cell.c +++ b/fs/afs/cell.c @@ -173,6 +173,7 @@ static struct afs_cell *afs_alloc_cell(struct afs_net *net, rcu_assign_pointer(cell->vl_servers, vllist); cell->dns_expiry = TIME64_MAX; + __clear_bit(AFS_CELL_FL_NO_LOOKUP_YET, &cell->flags); } else { cell->dns_expiry = ktime_get_real_seconds(); } -- cgit From cb6acd01e2e43fd8bad11155752b7699c3d0fb76 Mon Sep 17 00:00:00 2001 From: Mike Kravetz Date: Thu, 28 Feb 2019 16:22:02 -0800 Subject: hugetlbfs: fix races and page leaks during migration hugetlb pages should only be migrated if they are 'active'. The routines set/clear_page_huge_active() modify the active state of hugetlb pages. When a new hugetlb page is allocated at fault time, set_page_huge_active is called before the page is locked. Therefore, another thread could race and migrate the page while it is being added to page table by the fault code. This race is somewhat hard to trigger, but can be seen by strategically adding udelay to simulate worst case scheduling behavior. Depending on 'how' the code races, various BUG()s could be triggered. To address this issue, simply delay the set_page_huge_active call until after the page is successfully added to the page table. Hugetlb pages can also be leaked at migration time if the pages are associated with a file in an explicitly mounted hugetlbfs filesystem. For example, consider a two node system with 4GB worth of huge pages available. A program mmaps a 2G file in a hugetlbfs filesystem. It then migrates the pages associated with the file from one node to another. When the program exits, huge page counts are as follows: node0 1024 free_hugepages 1024 nr_hugepages node1 0 free_hugepages 1024 nr_hugepages Filesystem Size Used Avail Use% Mounted on nodev 4.0G 2.0G 2.0G 50% /var/opt/hugepool That is as expected. 2G of huge pages are taken from the free_hugepages counts, and 2G is the size of the file in the explicitly mounted filesystem. If the file is then removed, the counts become: node0 1024 free_hugepages 1024 nr_hugepages node1 1024 free_hugepages 1024 nr_hugepages Filesystem Size Used Avail Use% Mounted on nodev 4.0G 2.0G 2.0G 50% /var/opt/hugepool Note that the filesystem still shows 2G of pages used, while there actually are no huge pages in use. The only way to 'fix' the filesystem accounting is to unmount the filesystem If a hugetlb page is associated with an explicitly mounted filesystem, this information in contained in the page_private field. At migration time, this information is not preserved. To fix, simply transfer page_private from old to new page at migration time if necessary. There is a related race with removing a huge page from a file and migration. When a huge page is removed from the pagecache, the page_mapping() field is cleared, yet page_private remains set until the page is actually freed by free_huge_page(). A page could be migrated while in this state. However, since page_mapping() is not set the hugetlbfs specific routine to transfer page_private is not called and we leak the page count in the filesystem. To fix that, check for this condition before migrating a huge page. If the condition is detected, return EBUSY for the page. Link: http://lkml.kernel.org/r/74510272-7319-7372-9ea6-ec914734c179@oracle.com Link: http://lkml.kernel.org/r/20190212221400.3512-1-mike.kravetz@oracle.com Fixes: bcc54222309c ("mm: hugetlb: introduce page_huge_active") Signed-off-by: Mike Kravetz Reviewed-by: Naoya Horiguchi Cc: Michal Hocko Cc: Andrea Arcangeli Cc: "Kirill A . Shutemov" Cc: Mel Gorman Cc: Davidlohr Bueso Cc: [mike.kravetz@oracle.com: v2] Link: http://lkml.kernel.org/r/7534d322-d782-8ac6-1c8d-a8dc380eb3ab@oracle.com [mike.kravetz@oracle.com: update comment and changelog] Link: http://lkml.kernel.org/r/420bcfd6-158b-38e4-98da-26d0cd85bd01@oracle.com Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/hugetlbfs/inode.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'fs') diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index 32920a10100e..a7fa037b876b 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -859,6 +859,18 @@ static int hugetlbfs_migrate_page(struct address_space *mapping, rc = migrate_huge_page_move_mapping(mapping, newpage, page); if (rc != MIGRATEPAGE_SUCCESS) return rc; + + /* + * page_private is subpool pointer in hugetlb pages. Transfer to + * new page. PagePrivate is not associated with page_private for + * hugetlb pages and can not be set here as only page_huge_active + * pages can be migrated. + */ + if (page_private(page)) { + set_page_private(newpage, page_private(page)); + set_page_private(page, 0); + } + if (mode != MIGRATE_SYNC_NO_COPY) migrate_page_copy(newpage, page); else -- cgit