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authorCharan Teja Kalla <quic_charante@quicinc.com>2022-03-22 14:46:48 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2022-03-22 15:57:10 -0700
commit08095d6310a7ce43256b4251577bc66a25c6e1a6 (patch)
tree3ef5590f09453846a696b7c7885e19e5bf1389fd /mm/madvise.c
parent5bd009c7c9a9e888077c07535dc0c70aeab242c3 (diff)
mm: madvise: skip unmapped vma holes passed to process_madvise
The process_madvise() system call is expected to skip holes in vma passed through 'struct iovec' vector list. But do_madvise, which process_madvise() calls for each vma, returns ENOMEM in case of unmapped holes, despite the VMA is processed. Thus process_madvise() should treat ENOMEM as expected and consider the VMA passed to as processed and continue processing other vma's in the vector list. Returning -ENOMEM to user, despite the VMA is processed, will be unable to figure out where to start the next madvise. Link: https://lkml.kernel.org/r/4f091776142f2ebf7b94018146de72318474e686.1647008754.git.quic_charante@quicinc.com Fixes: ecb8ac8b1f14("mm/madvise: introduce process_madvise() syscall: an external memory hinting API") Signed-off-by: Charan Teja Kalla <quic_charante@quicinc.com> Cc: David Rientjes <rientjes@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Nadav Amit <nadav.amit@gmail.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/madvise.c')
-rw-r--r--mm/madvise.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/mm/madvise.c b/mm/madvise.c
index df59937c75e3..89490c859c3f 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -1428,9 +1428,16 @@ SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec,
while (iov_iter_count(&iter)) {
iovec = iov_iter_iovec(&iter);
+ /*
+ * do_madvise returns ENOMEM if unmapped holes are present
+ * in the passed VMA. process_madvise() is expected to skip
+ * unmapped holes passed to it in the 'struct iovec' list
+ * and not fail because of them. Thus treat -ENOMEM return
+ * from do_madvise as valid and continue processing.
+ */
ret = do_madvise(mm, (unsigned long)iovec.iov_base,
iovec.iov_len, behavior);
- if (ret < 0)
+ if (ret < 0 && ret != -ENOMEM)
break;
iov_iter_advance(&iter, iovec.iov_len);
}