aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/mtd/nand/nandsim.c
diff options
context:
space:
mode:
authorArtem Bityutskiy <Artem.Bityutskiy@nokia.com>2007-08-28 13:33:32 -0400
committerDavid Woodhouse <dwmw2@infradead.org>2007-09-06 05:16:22 -0400
commit98b830d26095007aeb04041147b93d2b74e0a0c0 (patch)
tree1008ba153bf8590de8c8daa083c6315626bf0530 /drivers/mtd/nand/nandsim.c
parent241651d04d672fb685b2874707016cbbf95931e5 (diff)
[MTD] [NAND] nandsim: avoid deadlocking FS
Make nandsim use GFP_NOFS when allocating memory, because it might be used by a file-system (e.g. UBIFS2) which means, if we are short of memory, we may deadlock. Indee, UBIFS is holding a lock, writes to the media, reaches this place in NANDsim, kmalloc does not find the requested amount of RAM, calls memory shrinker, which decides to writeback inodes, calls FS, and it deadlocks on the lock which is already being held. Below is the UBIFS backtrace which demonstrates that: [<c03717dc>] __mutex_lock_slowpath+0xc8/0x2e6 [<c0371a16>] mutex_lock+0x1c/0x1f [<f8b9d076>] reserve_space+0x3d/0xa9 [ubifs] [<f8b9d1bd>] make_one_reservation+0x2b/0x86 [ubifs] [<f8b9d3fc>] ubifs_jrn_write_block+0xda/0x12f [ubifs] [<f8b9ff3a>] ubifs_writepage+0x11d/0x1ec [ubifs] [<c015d6ab>] shrink_inactive_list+0x7fa/0x969 [<c015d8c8>] shrink_zone+0xae/0x10c [<c015e3b4>] try_to_free_pages+0x159/0x251 [<c015980a>] __alloc_pages+0x125/0x2f0 [<c016ff6a>] cache_alloc_refill+0x380/0x6ba [<c01703f3>] __kmalloc+0x14f/0x157 [<f885722a>] do_state_action+0xab7/0xc74 [nandsim] [<f885760c>] switch_state+0x225/0x402 [nandsim] [<f8857e7e>] ns_hwcontrol+0x3e2/0x620 [nandsim] [<f8862f53>] nand_command+0x2e/0x1a5 [nand] [<f8861ad8>] nand_write_page+0x4a/0x9a [nand] [<f88617b4>] nand_do_write_ops+0x1cf/0x343 [nand] [<f8861a70>] nand_write+0x88/0xa6 [nand] [<f8850b0e>] part_write+0x72/0x8b [mtd] [<f88e19c5>] ubi_io_write+0x189/0x29c [ubi] [<f88dfb98>] ubi_eba_write_leb+0xb6/0x699 [ubi] [<f88def93>] ubi_leb_write+0xe4/0xe9 [ubi] [<f8ba3b82>] ubifs_wbuf_write_nolock+0x333/0x4c9 [ubifs] [<f8b9d28c>] write_node+0x74/0x8e [ubifs] [<f8b9d422>] ubifs_jrn_write_block+0x100/0x12f [ubifs] [<f8b9ff3a>] ubifs_writepage+0x11d/0x1ec [ubifs] [<c0159e5b>] __writepage+0xb/0x26 [<c015a318>] write_cache_pages+0x203/0x2d9 [<c015a411>] generic_writepages+0x23/0x2d [<c015a452>] do_writepages+0x37/0x39 [<c018e24a>] __writeback_single_inode+0x96/0x399 [<c018e903>] sync_sb_inodes+0x1a3/0x274 [<c018ebf3>] writeback_inodes+0xa6/0xd8 [<c015a9dd>] background_writeout+0x86/0x9e [<c015ae9c>] pdflush+0xfb/0x1b6 [<c01387d7>] kthread+0x37/0x59 [<c0104dc3>] kernel_thread_helper+0x7/0x14 The deadlock is funny because it starts in pdflush/writeback, and comes back to writeback, then deadlocks. It seems we should look carefully for other places in UBI and MTD and use GFP_NOFS instead of GFP_KERNEL. Caught-by: Adrian Hunter <ext-adrian.hunter@nokia.com> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Diffstat (limited to 'drivers/mtd/nand/nandsim.c')
-rw-r--r--drivers/mtd/nand/nandsim.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/drivers/mtd/nand/nandsim.c b/drivers/mtd/nand/nandsim.c
index 205df0f771fe..a7574807dc46 100644
--- a/drivers/mtd/nand/nandsim.c
+++ b/drivers/mtd/nand/nandsim.c
@@ -1272,7 +1272,13 @@ static int prog_page(struct nandsim *ns, int num)
1272 mypage = NS_GET_PAGE(ns); 1272 mypage = NS_GET_PAGE(ns);
1273 if (mypage->byte == NULL) { 1273 if (mypage->byte == NULL) {
1274 NS_DBG("prog_page: allocating page %d\n", ns->regs.row); 1274 NS_DBG("prog_page: allocating page %d\n", ns->regs.row);
1275 mypage->byte = kmalloc(ns->geom.pgszoob, GFP_KERNEL); 1275 /*
1276 * We allocate memory with GFP_NOFS because a flash FS may
1277 * utilize this. If it is holding an FS lock, then gets here,
1278 * then kmalloc runs writeback which goes to the FS again
1279 * and deadlocks. This was seen in practice.
1280 */
1281 mypage->byte = kmalloc(ns->geom.pgszoob, GFP_NOFS);
1276 if (mypage->byte == NULL) { 1282 if (mypage->byte == NULL) {
1277 NS_ERR("prog_page: error allocating memory for page %d\n", ns->regs.row); 1283 NS_ERR("prog_page: error allocating memory for page %d\n", ns->regs.row);
1278 return -1; 1284 return -1;