| Message ID | 20201001125055.5042-1-cai@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v3] pipe: Fix memory leaks in create_pipe_files() | expand |
On Thu, Oct 01, 2020 at 08:50:55AM -0400, Qian Cai wrote: > Calling pipe2() with O_NOTIFICATION_PIPE could results in memory leaks > in an error path or CONFIG_WATCH_QUEUE=n. Plug them. [snip the copy of bug report] No objections on the patch itself, but commit message is just about unreadable. How about something along the lines of the following? ======================= Calling pipe2() with O_NOTIFICATION_PIPE could results in memory leaks unless watch_queue_init() is successful. In case of watch_queue_init() failure in pipe2() we are left with inode and pipe_inode_info instances that need to be freed. That failure exit has been introduced in commit c73be61cede5 ("pipe: Add general notification queue support") and its handling should've been identical to nearby treatment of alloc_file_pseudo() failures - it is dealing with the same situation. As it is, the mainline kernel leaks in that case. Another problem is that CONFIG_WATCH_QUEUE and !CONFIG_WATCH_QUEUE cases are treated differently (and the former leaks just pipe_inode_info, the latter - both pipe_inode_info and inode). Fixed by providing a dummy wath_queue_init() in !CONFIG_WATCH_QUEUE case and by having failures of wath_queue_init() handled the same way we handle alloc_file_pseudo() ones. Fixes: c73be61cede5 ("pipe: Add general notification queue support") Signed-off-by: Qian Cai <cai@redhat.com> =======================
On Thu, 2020-10-01 at 14:16 +0100, Al Viro wrote: > On Thu, Oct 01, 2020 at 08:50:55AM -0400, Qian Cai wrote: > > Calling pipe2() with O_NOTIFICATION_PIPE could results in memory leaks > > in an error path or CONFIG_WATCH_QUEUE=n. Plug them. > > [snip the copy of bug report] > > No objections on the patch itself, but commit message is just about > unreadable. How about something along the lines of the following? > > ======================= > Calling pipe2() with O_NOTIFICATION_PIPE could results in memory > leaks unless watch_queue_init() is successful. > > In case of watch_queue_init() failure in pipe2() we are left > with inode and pipe_inode_info instances that need to be freed. That > failure exit has been introduced in commit c73be61cede5 ("pipe: Add > general notification queue support") and its handling should've been > identical to nearby treatment of alloc_file_pseudo() failures - it > is dealing with the same situation. As it is, the mainline kernel > leaks in that case. > > Another problem is that CONFIG_WATCH_QUEUE and !CONFIG_WATCH_QUEUE > cases are treated differently (and the former leaks just pipe_inode_info, > the latter - both pipe_inode_info and inode). > > Fixed by providing a dummy wath_queue_init() in !CONFIG_WATCH_QUEUE > case and by having failures of wath_queue_init() handled the same way > we handle alloc_file_pseudo() ones. > > Fixes: c73be61cede5 ("pipe: Add general notification queue support") > Signed-off-by: Qian Cai <cai@redhat.com> > ======================= Thanks Al. This looks very good to me.
On Thu, Oct 01, 2020 at 09:37:02AM -0400, Qian Cai wrote: > > Fixed by providing a dummy wath_queue_init() in !CONFIG_WATCH_QUEUE watch_queue_init(), that is > > case and by having failures of wath_queue_init() handled the same way ditto > > we handle alloc_file_pseudo() ones. > > > > Fixes: c73be61cede5 ("pipe: Add general notification queue support") > > Signed-off-by: Qian Cai <cai@redhat.com> > > ======================= > > Thanks Al. This looks very good to me. Applied with that commit message (and typos above corrected) to #fixes and pushed
diff --git a/fs/pipe.c b/fs/pipe.c index 60dbee457143..f5d74ba1bf8c 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -913,19 +913,18 @@ int create_pipe_files(struct file **res, int flags) { struct inode *inode = get_pipe_inode(); struct file *f; + int error; if (!inode) return -ENFILE; if (flags & O_NOTIFICATION_PIPE) { -#ifdef CONFIG_WATCH_QUEUE - if (watch_queue_init(inode->i_pipe) < 0) { + error = watch_queue_init(inode->i_pipe); + if (error) { + free_pipe_info(inode->i_pipe); iput(inode); - return -ENOMEM; + return error; } -#else - return -ENOPKG; -#endif } f = alloc_file_pseudo(inode, pipe_mnt, "", diff --git a/include/linux/watch_queue.h b/include/linux/watch_queue.h index 5e08db2adc31..c994d1b2cdba 100644 --- a/include/linux/watch_queue.h +++ b/include/linux/watch_queue.h @@ -122,6 +122,12 @@ static inline void remove_watch_list(struct watch_list *wlist, u64 id) */ #define watch_sizeof(STRUCT) (sizeof(STRUCT) << WATCH_INFO_LENGTH__SHIFT) +#else +static inline int watch_queue_init(struct pipe_inode_info *pipe) +{ + return -ENOPKG; +} + #endif #endif /* _LINUX_WATCH_QUEUE_H */
Calling pipe2() with O_NOTIFICATION_PIPE could results in memory leaks in an error path or CONFIG_WATCH_QUEUE=n. Plug them. unreferenced object 0xc00000141114a0d8 (size 992): comm "trinity-c61", pid 1353192, jiffies 4296255779 (age 25989.560s) hex dump (first 32 bytes): 80 11 00 00 e8 03 00 00 00 00 00 00 00 00 00 00 ................ ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ backtrace: [<00000000abff13d7>] kmem_cache_alloc+0x1b4/0x470 [<000000009502e5d5>] alloc_inode+0xd0/0x130 [<00000000ca1c1a21>] new_inode_pseudo+0x1c/0x80 new_inode_pseudo at fs/inode.c:932 [<000000000c01d1d6>] create_pipe_files+0x48/0x2d0 get_pipe_inode at fs/pipe.c:874 (inlined by) create_pipe_files at fs/pipe.c:914 [<00000000d13ff4c4>] __do_pipe_flags+0x50/0x120 __do_pipe_flags at fs/pipe.c:965 [<0000000003941e42>] do_pipe2+0x3c/0x100 do_pipe2 at fs/pipe.c:1013 [<00000000a006b818>] sys_pipe2+0x1c/0x30 __se_sys_pipe2 at fs/pipe.c:1028 [<00000000a6925b55>] system_call_exception+0xf8/0x1d0 [<000000001c6b0740>] system_call_common+0xe8/0x218 unreferenced object 0xc000001f575ce600 (size 512): comm "trinity-c61", pid 1353192, jiffies 4296255779 (age 25989.560s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 ad 4e ad de .............N.. ff ff ff ff 00 00 00 00 ff ff ff ff ff ff ff ff ................ backtrace: [<00000000d74d5e3a>] kmem_cache_alloc_trace+0x1c4/0x2d0 [<0000000061cbc9cb>] alloc_pipe_info+0x88/0x2c0 kmalloc at include/linux/slab.h:554 (inlined by) kzalloc at include/linux/slab.h:666 (inlined by) alloc_pipe_info at fs/pipe.c:793 [<00000000efd6129c>] create_pipe_files+0x6c/0x2d0 get_pipe_inode at fs/pipe.c:883 (inlined by) create_pipe_files at fs/pipe.c:914 [<00000000d13ff4c4>] __do_pipe_flags+0x50/0x120 [<0000000003941e42>] do_pipe2+0x3c/0x100 [<00000000a006b818>] sys_pipe2+0x1c/0x30 [<00000000a6925b55>] system_call_exception+0xf8/0x1d0 [<000000001c6b0740>] system_call_common+0xe8/0x218 unreferenced object 0xc000000d94f20400 (size 1024): comm "trinity-c61", pid 1353192, jiffies 4296255779 (age 25989.560s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<00000000e60ee00f>] __kmalloc+0x1e4/0x330 [<00000000130e8cc8>] alloc_pipe_info+0x154/0x2c0 kmalloc_array at include/linux/slab.h:594 (inlined by) kcalloc at include/linux/slab.h:605 (inlined by) alloc_pipe_info at fs/pipe.c:810 [<00000000efd6129c>] create_pipe_files+0x6c/0x2d0 [<00000000d13ff4c4>] __do_pipe_flags+0x50/0x120 [<0000000003941e42>] do_pipe2+0x3c/0x100 [<00000000a006b818>] sys_pipe2+0x1c/0x30 [<00000000a6925b55>] system_call_exception+0xf8/0x1d0 [<000000001c6b0740>] system_call_common+0xe8/0x218 Fixes: c73be61cede5 ("pipe: Add general notification queue support") Signed-off-by: Qian Cai <cai@redhat.com> --- fs/pipe.c | 11 +++++------ include/linux/watch_queue.h | 6 ++++++ 2 files changed, 11 insertions(+), 6 deletions(-) base-commit: 60e720931556fc1034d0981460164dcf02697679