From 5f6f12ccf3aa42cfc0c5bde9228df0c843dd63f7 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 9 May 2011 16:04:11 +0200 Subject: [PATCH] libata: fix oops when LPM is used with PMP ae01b2493c (libata: Implement ATA_FLAG_NO_DIPM and apply it to mcp65) added ATA_FLAG_NO_DIPM and made ata_eh_set_lpm() check the flag. However, @ap is NULL if @link points to a PMP link and thus the unconditional @ap->flags dereference leads to the following oops. BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 IP: [] ata_eh_recover+0x9a1/0x1510 ... Pid: 295, comm: scsi_eh_4 Tainted: P 2.6.38.5-core2 #1 System76, Inc. Serval Professional/Serval Professional RIP: 0010:[] [] ata_eh_recover+0x9a1/0x1510 RSP: 0018:ffff880132defbf0 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff880132f40000 RCX: 0000000000000000 RDX: ffff88013377c000 RSI: ffff880132f40000 RDI: 0000000000000000 RBP: ffff880132defce0 R08: ffff88013377dc58 R09: ffff880132defd98 R10: 0000000000000000 R11: 00000000ffffffff R12: 0000000000000000 R13: 0000000000000000 R14: ffff88013377c000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8800bf700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000018 CR3: 0000000001a03000 CR4: 00000000000406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process scsi_eh_4 (pid: 295, threadinfo ffff880132dee000, task ffff880133b416c0) Stack: 0000000000000000 ffff880132defcc0 0000000000000000 ffff880132f42738 ffffffff813ee8f0 ffffffff813eefe0 ffff880132defd98 ffff88013377f190 ffffffffa00b3e30 ffffffff813ef030 0000000032defc60 ffff880100000000 Call Trace: [] sata_pmp_error_handler+0x607/0xc30 [] ahci_error_handler+0x1f/0x70 [libahci] [] ata_scsi_error+0x5be/0x900 [] scsi_error_handler+0x124/0x650 [] kthread+0x96/0xa0 [] kernel_thread_helper+0x4/0x10 Code: 8b 95 70 ff ff ff b8 00 00 00 00 48 3b 9a 10 2e 00 00 48 0f 44 c2 48 89 85 70 ff ff ff 48 8b 8d 70 ff ff ff f6 83 69 02 00 00 01 <48> 8b 41 18 0f 85 48 01 00 00 48 85 c9 74 12 48 8b 51 08 48 83 RIP [] ata_eh_recover+0x9a1/0x1510 RSP CR2: 0000000000000018 Fix it by testing @link->ap->flags instead. stable: ATA_FLAG_NO_DIPM was added during 2.6.39 cycle but was backported to 2.6.37 and 38. This is a fix for that and thus also applicable to 2.6.37 and 38. Signed-off-by: Tejun Heo Reported-by: "Nathan A. Mourey II" LKML-Reference: <1304555277.2059.2.camel@localhost.localdomain> Cc: Connor H Cc: stable@kernel.org Signed-off-by: Jeff Garzik --- drivers/ata/libata-eh.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c index f26f2fe3480a..dad9fd660f37 100644 --- a/drivers/ata/libata-eh.c +++ b/drivers/ata/libata-eh.c @@ -3316,7 +3316,7 @@ static int ata_eh_set_lpm(struct ata_link *link, enum ata_lpm_policy policy, struct ata_eh_context *ehc = &link->eh_context; struct ata_device *dev, *link_dev = NULL, *lpm_dev = NULL; enum ata_lpm_policy old_policy = link->lpm_policy; - bool no_dipm = ap->flags & ATA_FLAG_NO_DIPM; + bool no_dipm = link->ap->flags & ATA_FLAG_NO_DIPM; unsigned int hints = ATA_LPM_EMPTY | ATA_LPM_HIPM; unsigned int err_mask; int rc; -- 2.39.5