On Thu, May 09, 2013 at 03:08:15PM +0800, Li Zefan wrote: > Cc: Naoya Horiguchi <[email protected]> > > On 2013/5/9 12:35, Dave Jones wrote: > > Just saw this on v3.9-11789-ge0fd9af while fuzz-testing. > > > > [ 163.917836] BUG: unable to handle kernel NULL pointer dereference at > > 0000000000000008 > > [ 163.918984] IP: [<ffffffff812c48ed>] newseg+0x10d/0x390 > > The patch below should fix it. > > =========================== > > [PATCH] shm: fix null pointer deref when userspace specifies invalid hugepage > size > > Dave reported an oops triggered by trinity: > > [ 163.917836] BUG: unable to handle kernel NULL pointer dereference at > 0000000000000008 > [ 163.918984] IP: [<ffffffff812c48ed>] newseg+0x10d/0x390 > [ 163.919705] PGD cf8c1067 PUD cf8c2067 PMD 0 > [ 163.920326] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC > [ 163.929949] CPU: 2 PID: 7636 Comm: trinity-child2 Not tainted 3.9.0+#67 > ... > [ 163.953629] Call Trace: > [ 163.957706] [<ffffffff812be322>] ipcget+0x182/0x380 > [ 163.962123] [<ffffffff810b99a5>] ?trace_hardirqs_on_caller+0x115/0x1e0 > [ 163.966752] [<ffffffff812c559a>] SyS_shmget+0x5a/0x60 > [ 163.971163] [<ffffffff812c47e0>] ? shm_close+0x140/0x140 > [ 163.975590] [<ffffffff812c3e60>] ? shm_release+0x50/0x50 > [ 163.979991] [<ffffffff812c3df0>] ? shm_get_unmapped_area+0x20/0x20 > [ 163.984499] [<ffffffff816caa14>] tracesys+0xdd/0xe2 > > This bug was introduced by commit af73e4d9506d3b797509f3c030e7dcd554f7d9c4 > ("hugetlbfs: fix mmap failure in unaligned size request"). > > Reported-by: Dave Jones <[email protected]> > Cc: <[email protected]> > Signed-off-by: Li Zefan <[email protected]>
Thank you. Reviewed-by: Naoya Horiguchi <[email protected]> > --- > > Previously it would return -ENODEV, but seems -EINVAL is more appropriate. Agreed. Thanks, Naoya > --- > ipc/shm.c | 8 +++++++- > mm/mmap.c | 8 ++++++-- > 2 files changed, 13 insertions(+), 3 deletions(-) > > diff --git a/ipc/shm.c b/ipc/shm.c > index 34af1fe..7e199fa 100644 > --- a/ipc/shm.c > +++ b/ipc/shm.c > @@ -493,7 +493,13 @@ static int newseg(struct ipc_namespace *ns, struct > ipc_params *params) > if (shmflg & SHM_HUGETLB) { > struct hstate *hs = hstate_sizelog((shmflg >> SHM_HUGE_SHIFT) > & SHM_HUGE_MASK); > - size_t hugesize = ALIGN(size, huge_page_size(hs)); > + size_t hugesize; > + > + if (!hs) { > + error = -EINVAL; > + goto no_file; > + } > + hugesize = ALIGN(size, huge_page_size(hs)); > > /* hugetlb_file_setup applies strict accounting */ > if (shmflg & SHM_NORESERVE) > diff --git a/mm/mmap.c b/mm/mmap.c > index 1ae21d6..f681e18 100644 > --- a/mm/mmap.c > +++ b/mm/mmap.c > @@ -1367,9 +1367,13 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, > unsigned long, len, > len = ALIGN(len, huge_page_size(hstate_file(file))); > } else if (flags & MAP_HUGETLB) { > struct user_struct *user = NULL; > + struct hstate *hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & > + SHM_HUGE_MASK); > > - len = ALIGN(len, huge_page_size(hstate_sizelog( > - (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK))); > + if (!hs) > + return -EINVAL; > + > + len = ALIGN(len, huge_page_size(hs)); > /* > * VM_NORESERVE is used because the reservations will be > * taken when vm_ops->mmap() is called > -- > 1.8.0.2 > > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
