kernel/fs/proc, branch linux-3.11.y

mm: /proc/pid/pagemap: inspect _PAGE_SOFT_DIRTY only on present pages

2013-11-13T03:08:11Z

commit e9cdd6e771580e6ff872e5c64e8b766972c7d1bc upstream. If a page we are inspecting is in swap we may occasionally report it as having soft dirty bit (even if it is clean). The pte_soft_dirty helper should be called on present pte only. Signed-off-by: Cyrill Gorcunov Cc: Pavel Emelyanov Cc: Andy Lutomirski Cc: Matt Mackall Cc: Xiao Guangrong Cc: Marcelo Tosatti Cc: KOSAKI Motohiro Cc: Stephen Rothwell Cc: Peter Zijlstra Cc: "Aneesh Kumar K.V" Reviewed-by: Naoya Horiguchi Cc: Mel Gorman Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

proc: Restrict mounting the proc filesystem

2013-09-27T00:21:57Z

commit aee1c13dd0f6c2fc56e0e492b349ee8ac655880f upstream. Don't allow mounting the proc filesystem unless the caller has CAP_SYS_ADMIN rights over the pid namespace. The principle here is if you create or have capabilities over it you can mount it, otherwise you get to live with what other people have mounted. Andy pointed out that this is needed to prevent users in a user namespace from remounting proc and specifying different hidepid and gid options on already existing proc mounts. Reported-by: Andy Lutomirski Signed-off-by: "Eric W. Biederman" Signed-off-by: Greg Kroah-Hartman

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2013-08-25T19:25:38Z

Pull vfs fixes from Al Viro: "Assorted fixes from the last week or so" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: VFS: collect_mounts() should return an ERR_PTR bfs: iget_locked() doesn't return an ERR_PTR efs: iget_locked() doesn't return an ERR_PTR() proc: kill the extra proc_readfd_common()->dir_emit_dots() cope with potentially long ->d_dname() output for shmem/hugetlb

proc: kill the extra proc_readfd_common()->dir_emit_dots()

2013-08-24T16:10:22Z

proc_readfd_common() does dir_emit_dots() twice in a row, we need to do this only once. Signed-off-by: Oleg Nesterov Signed-off-by: Al Viro

proc: more readdir conversion bug-fixes

2013-08-19T23:26:12Z

In the previous commit, Richard Genoud fixed proc_root_readdir(), which had lost the check for whether all of the non-process /proc entries had been returned or not. But that in turn exposed _another_ bug, namely that the original readdir conversion patch had yet another problem: it had lost the return value of proc_readdir_de(), so now checking whether it had completed successfully or not didn't actually work right anyway. This reinstates the non-zero return for the "end of base entries" that had also gotten lost in commit f0c3b5093add ("[readdir] convert procfs"). So now you get all the base entries *and* you get all the process entries, regardless of getdents buffer size. (Side note: the Linux "getdents" manual page actually has a nice example application for testing getdents, which can be easily modified to use different buffers. Who knew? Man-pages can be useful) Reported-by: Emmanuel Benisty Reported-by: Marc Dionne Cc: Richard Genoud Cc: Al Viro Signed-off-by: Linus Torvalds

proc: return on proc_readdir error

2013-08-19T16:47:27Z

Commit f0c3b5093add ("[readdir] convert procfs") introduced a bug on the listing of the proc file-system. The return value of proc_readdir() isn't tested anymore in the proc_root_readdir function. This lead to an "interesting" behaviour when we are using the getdents() system call with a buffer too small: instead of failing, it returns the first entries of /proc (enough to fill the given buffer), plus the PID directories. This is not triggered on glibc (as getdents is called with a 32KB buffer), but on uclibc, the buffer size is only 1KB, thus some proc entries are missing. See https://lkml.org/lkml/2013/8/12/288 for more background. Signed-off-by: Richard Genoud Cc: Al Viro Cc: Andrew Morton Signed-off-by: Linus Torvalds

fs/proc/task_mmu.c: fix buffer overflow in add_page_map()

2013-08-14T00:57:50Z

Recently we met quite a lot of random kernel panic issues after enabling CONFIG_PROC_PAGE_MONITOR. After debuggind we found this has something to do with following bug in pagemap: In struct pagemapread: struct pagemapread { int pos, len; pagemap_entry_t *buffer; bool v2; }; pos is number of PM_ENTRY_BYTES in buffer, but len is the size of buffer, it is a mistake to compare pos and len in add_page_map() for checking buffer is full or not, and this can lead to buffer overflow and random kernel panic issue. Correct len to be total number of PM_ENTRY_BYTES in buffer. [akpm@linux-foundation.org: document pagemapread.pos and .len units, fix PM_ENTRY_BYTES definition] Signed-off-by: Yonghua Zheng Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: save soft-dirty bits on file pages

2013-08-14T00:57:48Z

Andy reported that if file page get reclaimed we lose the soft-dirty bit if it was there, so save _PAGE_BIT_SOFT_DIRTY bit when page address get encoded into pte entry. Thus when #pf happens on such non-present pte we can restore it back. Reported-by: Andy Lutomirski Signed-off-by: Cyrill Gorcunov Acked-by: Pavel Emelyanov Cc: Matt Mackall Cc: Xiao Guangrong Cc: Marcelo Tosatti Cc: KOSAKI Motohiro Cc: Stephen Rothwell Cc: Peter Zijlstra Cc: "Aneesh Kumar K.V" Cc: Minchan Kim Cc: Wanpeng Li Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: save soft-dirty bits on swapped pages

2013-08-14T00:57:47Z

Andy Lutomirski reported that if a page with _PAGE_SOFT_DIRTY bit set get swapped out, the bit is getting lost and no longer available when pte read back. To resolve this we introduce _PTE_SWP_SOFT_DIRTY bit which is saved in pte entry for the page being swapped out. When such page is to be read back from a swap cache we check for bit presence and if it's there we clear it and restore the former _PAGE_SOFT_DIRTY bit back. One of the problem was to find a place in pte entry where we can save the _PTE_SWP_SOFT_DIRTY bit while page is in swap. The _PAGE_PSE was chosen for that, it doesn't intersect with swap entry format stored in pte. Reported-by: Andy Lutomirski Signed-off-by: Cyrill Gorcunov Acked-by: Pavel Emelyanov Cc: Matt Mackall Cc: Xiao Guangrong Cc: Marcelo Tosatti Cc: KOSAKI Motohiro Cc: Stephen Rothwell Cc: Peter Zijlstra Cc: "Aneesh Kumar K.V" Reviewed-by: Minchan Kim Reviewed-by: Wanpeng Li Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

s390/kdump: Disable mmap for s390

2013-07-18T11:40:18Z

The kdump mmap patch series (git commit 83086978c63afd7c73e1c) directly map the PT_LOADs to memory. On s390 this does not work because the copy_from_oldmem() function swaps [0,crashkernel size] with [crashkernel base, crashkernel base+crashkernel size]. The swap int copy_from_oldmem() was done in order correctly implement /dev/oldmem. See: http://marc.info/?l=kexec&m=136940802511603&w=2 Signed-off-by: Michael Holzheu Signed-off-by: Martin Schwidefsky